Well that's the thing about words...they have connotations and associations that exceed their literal meanings. And yes, generally, "active" has more positive connotations than "passive."
Relatedly, it's not the best word to actually describe what you are trying to describe. The 5e play loop does not situate the player in an inherently passive position. Passive players are those that are not engaged or have no reaction to the world as presented. I would say that 5e players are reactive: the DM initiates the play loop, the player responds, and then the DM responds in turn. The GM has more work to do in their steps, but that does not mean that all the puzzle-solving and tactical combat-having is passive (let alone the character-building and backstory-creating, which may as well be a pillar of play).
It is and it isn't. The part that isn't is that the GM doesn't have to honor the reaction by the players. And this is discounting bad faith or poor play -- if the players' reactions are not aligned with the GM's conception of the fiction, then they aren't honored. Effectively, in the usual mode of play for 5e, the GM is tightly constraining the players' options for their PCs with their situation. The players collectively learn and engage the fiction the GM presents within their limited channels. I mean, there's already quite a side discussion about what counts as engaging metachannels in play and what's allowable for action declarations by the players.
So, while there is a reactive element to play, it is still constrained and that constraint is largely the GM and how they allow for the fiction they've created and presented to be interacted with. Play isn't really just reaction/counter reaction, but rather hunting for the allowable reactions.
My prior example of how, in Rime, there is a fictional puzzle that can only be solved with one answer and that answer is not obvious (dispel magic is the only solution, but it's not clear that this is so) is a prime example of the kinds of constraints placed on the players by the GM's fiction, and how "react" isn't quite the right word. I mean, I did a lot of reacting to this puzzle, where I tried to destroy it physically (no roll allowed, action failed), to trying to smother the fire with snow and a wet cloak (no roll allowed, action failed), to attempting to use arcana to solve the problem via trying to figure out how to disrupt the magic (roll allowed, but meaningless, as the roll was to determine if I was allowed to know why the action failed).
So, yeah, here was a lot of reacting (and this is from a published adventure) that didn't matter at all, because I had to find the one allowed pathway and follow that. If this is the case, that's pretty passive as far as what play is allowed -- follow the path or the answer is no.
Perhaps more importantly, "passive" may or may not be how players describe their own experience with a system. For example, Call of Cthulhu scenarios are fairly linear, and a lot of what the keeper does is literally hand the players sheets with pre-made backstory. Yet from experience I've had, players find that experience to be engaging and dialogic, involving both their imagination and problem-solving skills. When considered in the whole range of ttrpgs, it's easy to forget that even traditional games and linear scenarios feel very "active" for a lot of people, new and continuing players. That feeling of engagement is what draws people to 5e as well.
Play here is pretty much the same as in 5e. It's just as passive. I've noted previously that I still find it fun, and that it can be very entertaining. This seems to be trying to talk up the play here, but I'm assuming that engaging in dialog with each other and using your imagination is a baseline for play of an RPG, so saying you meet baseline doesn't do much for advancing the claim that play isn't otherwise fairly passive.
To be clear, when we talk about playing an RPG, passive is referring to that play. If you imagine that passive is saying non-participatory, or that appeals to engaging in dialog or imagination defeat the claim, then you're missing the context of the claim. These are baseline to play of an RPG, and I'm not discussing degenerate play. So, with participation being baseline, what constitutes passive play? I've been clear on this.
Unlike me, you seem very confident that you can look at other people's games, and overwrite their own experiences.
Nope.
That if someone (and actually lots of people) say that they play 5e modules more or less by the book, and they find the time they spend with their characters to be active, collaborative, and engaging, you'll be able to step in with your "unromantic" analysis (with its already-set categories) and say, "nope, 5e is passive." That's what I mean when I say you are articulating a prescriptive, axiomatic perspective in these posts.
This isn't overwriting their experience. It's disagreeing with their characterization. It's like saying, "I went down the bunny slope at the ski lodge, and it is the most challenging and rewarding experience you can have on skis!" If I'm a skier, I'm going to look askance at this statement, even while I'll allow that that person felt challenged and rewarded. Disputing the qualitative claims made in general is not at all disputing the experience of the player. As I've said, I enjoy 5e as a player. My play is passive when compared to the possible scopes of play in RPGs. I'm okay with this. The experience can still be fun and rewarding. This doesn't change that there is little that the game expects of me.
Here's a reasonable test: if you run the same game for different players/characters, will the results be similar? In many 5e games, the answer to this is yes. Certainly for any of the published adventures. The same things will occur, the same general results obtained. Differences will be in details. Players that complete Storm King's Thunder will all have rather similar stories about the events of the game. This is an indicator of that passive play. Even in a sandbox, if the GM is instantiating the same set of factions and goals, and not creating brand new prep differently for a separate playthrough, many things will be similar. You can see this for a small sandbox very clearly, like Isle of Dread. Stories of this game all have very many points of similarity.
This isn't a bad thing. Comparable results lead to increases in shared experiences which are what can create a sense of community within a hobby. I've enjoyed trading war stories. I ran three separate groups through Return to the Temple of Elemental Evil, and was engaged with the small differences -- some groups made choices that resulted in encountering fiction other groups didn't, and vice versa. But, overall, the stories told with these different players and different characters (especially characters) are not at all different in any substantial way. They all went through the moathouse, they all went to the crater, they all dealt with the temples, etc, etc. At a certain distance, the play is indistinguishable, and that distance isn't terribly far -- at the level of a moderately detailed synopsis. If this is the case, if who the players are and who the characters are do not really move the needle much, then I'm okay saying that play is passive here -- the goal is to uncover the fiction the GM has prepared. This was successfully done. Also, as a note, this adventure has some strong sandbox elements to it, so it's not a linear railroad.