Who else loves low level D&D, and why? Or why not?
There's a lot to unpack with this. It might be helpful to note that I am one of those gamers that gets to play a lot of not-D&D (/D&D-alikes), and some of my answers bleed into other games.
First of all, I generally dislike pretty high-level A/D&D. I think it was discovered fairly early that people weren't stopping at 'name level' like EGG and co assumed they would and they had the opportunity to rebuild upper level monsters/spells/items towards a more cohesive (thematically and mechanically), but didn't and now there's a whole lot of discordant cruft (every bit of which is someone's favorite thing) all there not-working-well-together forever. So yeah, I love me some not-super-high-level D&D.
Secondly, I love me some low-stakes fantasy. There's a neigh-infinite amount of save-the-world style fantasy novels, tv shows, movies, video games, and so forth. I find it rather satisfying to play a game where saving the family farm or stopping a bandit crew is a major story arc (instead of a single week's events as you level up). One of the best gaming sessions I ever undertook was with a bunch of engineering-minded players and where the PCs were travelling with peasant pilgrims and a merchant, the ford had washed out, and they had to get all the people, animals, and wagons across a wide stream/small river (without the grain in the wagons getting wet, etc.), and without leaving the wagons unattended (and thus potentially captured by opportunistic thieves) by martial capable on either side of the river. That's a reason why I like lower-level D&D (/
Beyond the Wall and other Stories), but that thematic style of gameplay is hardly specific to D&D (see also
Stonetop, etc.).
However, D&D does have some challenges (to the fun aspect) at lower levels. As others have mentioned, low-level PCs are fragile and don't have a lot of responses to various things. The low-level fragility is a big thing because a lot of characters will be fine...fine...fine...dead in a way that later levels and many other games don't have or have more nuance towards (or at the very least you can take steps against).
Beyond that, It is fun before your spells can solve everything to have to play around with ropes and pitons and caltrops and this lock is rusty does anyone have oil and that one is covered in grease did anyone buy soap and all that stuff for a while. However, D&D has a lot of boolean effects (you are either invisible or not, petrified or not; no level-1 petrified), so there are a lot of situations where you run into situation X and it's just a dead-end/roll a new character/go beg or buy a solution from a higher-level NPC.
So yeah, I do have some issues with low-level D&D; but I do love the scope of play it sits in.