If anything, /tlhg/ is as bad as it is now because mods pushed it to be.
If I recall correctly, as a general it was technically never on /co/ as, early on, mods just kept deleting Loud House threads and posts in them, forcing a general to be made on /trash/, before and during the very start of the show. This continued on into threads here being severely limited in what can be posted and discussed, ending up with "talkback" threads really just being an excuse to have a thread to not "spoil" the episode before downloads are out because no one goes into them.
It also doesn't help that the popular Nickelodeon shows tend to have really off fanbases due to being on a big network, so you get guys like the obvious samefag who shitposts other shows using Loud House or FOP or the other samefag who keeps making inane Loud House threads about nothing in particular, because he doens't know how to start a thread.
It's not on /trash/ because generals aren't allowed, it's on /trash/ because, for a long time, that was kind of the only place it could be discussed in full in any way.>>88343666
/tlhg/ is shit because it's forced to rely on a very tight-knit group of people to provide content as the show, itself, isn't one to bring up discussion of "lore" or what not, as the show's allure is the characters, how they interact, and the situations they can get in. There isn't really any ERP, unless you count "fics, but there is a lot of shitposting because when that tight-knit group of people isn't there, isn't making anything, or is waning and waxing with random people who may not even interact with the threads much, there isn't anything else to fill the void. It's gone on so long that people expect a certain speed of activity, and because it's on a board called /trash/, people think they're expected to post trash with no repercussions.
TL;DR, it's shit because people are bored and expect it to be.
Ironically, the actual hate is overblown by small threads with loud voices.