He is not a good friend to Okarin. In both Steins;Gate and Steins;Gate 0 he literally never takes Okarin's side on ANYTHING, like it doesn't matter who he's disagreeing with, he always disagrees with him. I get he's a useful hacker, sure, but he's also such a creep. I get that that's supposed to be his personality but it makes him so hateable to me. How does ANYONE want to be near him after the comments he makes about Nae (who's TWELVE) and every other girl around. He seems to resent Okarin for not going into the past with Suzuha (something that brings him unimaginable pain) and is happy to build the phonewave behind his back in the lab that Okarin rents. But when he has to do ONE thing to ENSURE that the daughter (who he also is constantly a weirdo about) will exist he's pathetic. Okarin is supposed to be the bad guy because he can't bear to see Kurisu die again, but when Itaru is too fat and peverted to get off his ass and make sure his daughter will exist in the future it's just seen as a minor annoyance.
And when Okarin was being Houoin Kyouma, yea it was cringe, but every time Itaru would say things to everyone else like "don't listen to him he's crazy", as if he doesn't go out of his way to try to make girls say gross things without them knowing it so that he can get off to it. When Maho had a knife to her neck in Steins;Gate 0 he was still making jokes about hentai. I can't see how anyone could like him.