The reason modern WoW is less toxic and tryhard despite the top end content being substantially more difficult than Classic, is because of the attitude fostered by the Classic fanbase from the very beginning.
“Retail is Disney”
“Retail participation trophies”
“Retail is for kids who don’t want to put effort into anything”
There were even people claiming Classic Ragnaros was going to be as difficult as Modern Mythic raid bosses:
and stuff like this:
Inflated egos, sense of superiority, etc.