No; just no. First of all: cursing like an animal is not helping anyone; it doesn’t help you because you could be calmer anyway and it doesn’t help them since they only see a hater.
Secondly and more importantly: above level 18 (or even above 15 for the newer players): this is getting in hard-core tier; it would be like saying banning people for leaving guilds.
Pugging is not causing his problems, he causes his problem. I want to pug because I want to avoid having a stable schedule in a guild like it’s a job; I understand though that would mean lower progress in game; I will not clear mythic raiding early and I will not do 5mans above 18 without major pain.