You're pretty much talking about conversing with people on the internet in general, mostly social media platforms. Bitcointalk isn't anything special. If anything, Bitcointalk is far less lax because you have benefit of being pseudonymous.
he speaks like a child. none of what he says is specific only to the Bitcointalk forum, or to any social networks. if he went out into the real world among real people and tried to communicate with anyone, he would notice that similar communication rules apply there. maybe in a slightly different form, but the essence is the same.