I used 4chan long before I used puahate. I first used 4chan in early 2006 when I was still 18. That said I wouldn't say the 4chan format is remotely similar to the reddit format.
I've been using forums since I was like 12 though, and most forums have a somewhat similar format, so I suppose that's why I'm more used to it. I didn't start using reddit until like 2010, which was long after I had been using forums and image boards. I never liked the reddit format. I never liked the faggy looking snoo. I never liked updoots and downdoots (even though that's part of the premise of the site). And of course there's the reddit community, but that's a separate issue.
I guess I can sort of understand being resistant to change though. Personally I still strongly dislike Discord even though everyone's on it now. I grew up using AIM/MSN/Yahoo messenger. Skype took a little getting used to but it wasn't too much of a problem. But I just hate using Discord, a lot. I only use it now because I don't have any other options because that's all everyone's using.