Why did people used to hate Fortnite so much?

For me personally:

a) I really dislike Multiplayer/PvP only games especially in the BR genre and those loosely in that area. Halo Infinite kinda sits in this for me. Feels like they didn't put as much effort into the single player campaign as much as they did the Multiplayer side. And I've LOVED the Halo series up to this point including 4 and 5.
b) There is of course the whole children aspect. And it's not just singling out Fortnite. I've been into other games in the past that I've had to give up because of a sudden influx of kids. I used to play RecRoom a lot as an example. But it seemed when they started adding 'pancake' support and added a mobile app, it just went downhill FAST. I haven't bothered to go back.
c) It does seem like they are trying way too hard these days to keep it relevant. Every time I turn around I see some new game mode or environment, the latest meme included somehow, some of the more obnoxious content creators shilling for them, etc..

That said, this is all my own personal view on it. Doesn't bother me if others play it or what they think about it. The game just simply isn't for me.