As a current League player & DBD veteran player, I can sadly confirm that DBD's community is worse when it comes to post game interactions; as many players will hold grudges for an insane amount of time/still try to go after you months after they had a bad game against you.
Meanwhile in League, you might receive a friendrequest by someone that will tell you to comit self harm (or just flame you), after which they'll immediately unfriend & block you. The entire interaction is optional as you can just decline the friend request. By the time you played the next game both sides will have likely forgotten the interaction. But on DBD players will stalk your socials & keep harassing you months if not years later, trying to pick fights anywhere they can.
I saw this on Reddit & I feel like I have some insight
I played LoL mostly 2012-2018 & then on & off after that. I have 8k hours on dbd
League is more casual toxicity, like yeah you’ll get flamed ingame for making mistakes/not playing optimally & sure my team will throw a slur here & there for not playing perfect but by the time I’m in the next match we all forget about the previous game.
I don’t know what it is about dbd that makes people take the game so personal but I’ve been legit STALKED for almost a year & a half for slugging someone, like full on finding my government name & continuos harassment for a game, & that’s just one experience.
Unfortunately dbd is more toxic