Bad players create toxicity? Sorry, but then we understand toxicity differently. I have never seen a bad player insult the good ones when being called out, only apologise and express willingness to learn. But I’ve seen too much of “bro, your DPS sucks” (followed by a kick from a party in WoW without any discussion).
It isn’t toxic to not know your class 100% or make an occasional mistake.
It could be toxic only in case of trolling, but that’s a completely different discussion.