Alright here is my schizo theory. Ralph knows full well that he has no audience, nobody (that's not an alog) pays attention to him. Especially in twitter. So his lies are aimed at accidental random people who may stumble upon his tweets knowing absolutely nothing about him or Rekieta or anything really, and he copes by imagining that some random nobodies think poorly of his enemies because of his tweets. I think he hopes that maybe, just maybe somebody, anybody will see it and think "wow, what a fagget" about the person Gunt is lying about.
Unrelated but... it's still my lunatic brain thinking about the ways Gunt brain might work. I think the examples of his "I'd tell you if I shit my pants" and "I'd tell you if I eat da poo" is very convenient little manipulation he does that serves multiple purposes. One of the things he tries to achieve with it is to trick himself (more than anybody else) that these things are not as embarrassing as they in reality are. He wants to convince himself that in reality he is not as disgusting as he is. These things are not so bad, and he'd admit them because of just how not big of a deal it is. It's not like it's so bad that's worth lying about or denying it. In fact denying it and claiming you don't eat the poo when you do eat it is stupid, it's so stupid it doesn't even make any sense. If I shit my pants I'd announce it, if I eat the poo I'd tell you all about it.
So in his mind it boils down to It's not at all embarrassing that I shart and lick shit.