Former wow players are not affecting this game in a negative way, i speak as a former wow player myself that came back to this game over half a year ago after getting sick of 'Boring Farming Azerite' expansion. I have been switching between wow and ffxiv for years, and the level of toxic players now is no different than before the wow mass exodus.
Every game has it's percentage of toxic players no mmo is without them. Some are just impatient and expect everything to be perfect every time, some take advantage of being behind an avatar to behave like that because they like it and would never dare do it to people faces in real life. That's just two reasons there are many not gonna list them all.
The main reason the toxicity level is much lower here is because people simply will not tolerate it and the player base will take action and self police to stop this sort of thing, the last time i saw it was about two weeks ago.
I was in an alliance raid, we were on the second to last boss and we wiped, not a big deal. Straight away one of the group starts kicking off about the fact that after this raid being out for a couple of years everyone should know what to do and we should not be wiping. So another player in the group a healer points out that not everyone is the group is a veteran, we had a fair number of sprouts and also had the notification that one or more were new to the duty and as such not everyone can be expected to be experts.
Well this toxic player did not like that, so he inspects the healers gear, next thing he is posting in party chat slamming the healer for his choice of melds by name, saying that he obviously does not have a clue how to play his class since he is using stupid melds, and is calling on the group to check out his terrible melds and saying how useless this player is. Of course the rest of us ignore this player and concentrate on the boss fight.
Now you would think this player would take a hint after we ignore him, but no. He switches to alliance chat and starts the same thing over again posting the healers name in alliance chat and slamming him in alliance chat just the same as he did in the party chat. Again he is completely ignored by everyone in the alliance party.
So we down the boss on the second try, one boss left and it is done. Shortly after the boss is downed vote kick pops up, reason harassment. The toxic player was kicked, so after half an hour in the run only one boss left he was booted and had to do another alliance raid from the beginning for his behaviour, so he lost half an hour of time over it.
Now i cannot say if this player has carried on in this manner in other runs or learned their lesson, but if they carried on doing this repeatedly the reports would end up getting him banned.
That is why toxic behaviour is more of a rare occurrence here and will continue to be. It will never stop completely, this again is true of any mmo. It is simply not tolerated here.