I would guess that's because no one's really advocating such. Well, that is not in the way that I believe you're stating.
There's more play in role-playing games than what just occurs between the players and the GM. For those who prefer playing in a pretend world that exists independently of the PCs, there's the game the GM (and the player) plays alone. In this aspect of roleplay the rules function not only as directions on what widgets can do what while at the table, but as guidelines to how to create a "pretend reality" wherein those (player or GM) who prefer to role-play as if the world exists independent of the PCs find help in creating that independent world based upon the rules expectations.
I don't think that's entirely true. A pretend world that exists independently of the PCs is still subject to the GM's narrative control whenever he wants things to happen. To some, that's a major advantage. If Crescentia declares war on Akklorash, the GM doesn't have to play through the overtures, making NPC Diplomacy checks to see whether the war is averted or not. He can if he likes: but he's deliberately making extra work for himself, and not everyone enjoys that extra work.
I believe that the split here isn't between "whether you think the world should exist independent of the PCs," it's the question of whether the rules are the foundation for what happens in the world, or whether what happens in the world is the foundation for the rules. If a sudden plague sweeps across a given country, one approach is to come up with mechanical effects for the plague and then apply them to each NPC by the rules; another is to determine how lethal it is, what NPCs die, and then figure out rules for the plague that reflect that. It's a top-down vs. bottom-up decision.
IMO, the design flaw is that minions do not fulfill any other role except to exist to interact with the PCs. This leaves those who enjoy role-playing in worlds that pretend exist outside of the PCs dissatisfied, be those people GMs or players.
Again, I think you're not necessarily representing the group you're talking about. I like worlds that exist outside of the PCs. I run worlds that exist outside of the PCs. But I don't require them to be mechanical outside of the PCs' interaction. This no doubt comes from the way I played back in college, where dice would come out only every other session or so and half the people we interacted with were never statted, but the concept of a world that exists and does things just isn't married to mechanical presence in my mind.
Minions are attritting mechanical-devices. They increase the difficulty in making the optimal powers choice to use harder (Damn! I used my daily on a minion!) while filling space based upon a preference for multiple opponent combat coupled with the focus on mobility found in 4e. They perform this function admirably, but they do such in a way that alienates other styles of play.
Generally speaking, I've found that if you're using your daily on a minion, the DM isn't describing things in much detail, or the players are naturally twitchy. Most players I've dealt with take their dailies fairly seriously, and save them for clear and obvious threats — discerning between rank-and-file orcs and the big badass with the bow who's filling Boromir full of arrows. The only times I've seen dailies used against minions in-game is when a PC throws an area-effect daily against a distinctly tough enemy and catches some minions in the burst. (I
have seen some encounter powers wasted on minions, to variable definitions of "waste," but not more than once for any given player. After that they pay more attention to description.)
I absolutely agree that they alienate other styles of play, but I'd have to say they don't really make things harder to strategize outside one of those incompatible styles of play. They add more challenge (do I move through the minion cluster to try and nail their boss with my encounter?), but in a fairly positive way.
Of course, my various groups took very well to 4e. Use that as whatever disclaimer you see fit.
Edit: Gah, with those other two posts, this looks like a dogpile. Hope you take this post in the spirit in which it was intended!