Tbh very rarely these days, have next to no reason to visit hc dungeons or lfr, but when I did, I don't see any positive influence from rude / obnoxious players, would be better off if they were filtered out for the sake of neutral / positive people.
Same thing when I played League of Legends, did I enjoy being flamed by random mongs who dive 1v5? Nope I'd rather have them chat banned or not see in my games altogether.
Shame no one did such research in WOW, but in LOL they actually did, a correlation between champion played and flaming in chat. The "big dick dps" or "1v1 me kid" types of champions had higher amount of toxic chat displayed than utility / group teamplay oriented champions.
If it was the same in WOW, well I guess filtering out toxic players would only improve the queue ratios rather than worsen it.