I think Moth going after MoistCr1TiKal is just another attempt at getting eyes on him. I could honestly see him trying to get Charlie's fans mad enough to attack him in his comments section. After all, hate comments and downvotes still count as engagement.
It's the only logical conclusion I can come up with since, as far as I'm aware, Charlie has never given Moth any reason to go after him.
Moth getting pissy at Wendigoon is amusing to me, if only because it's clear that it stems from jealousy, lol. Thing is, I don't think that it's solely because Wendigoon is more successful. I think that it's that it's because Wendigoon is successful while being honest about who he is and doesn't try to be some tryhard edgelord.
He makes videos on a variety of topics that he enjoys, so there's something for everyone. You can tell that he is genuinely interested in what he is talking about (unlike Moth, who, most of the time, seems completely bored with whatever he is talking about). He also isn't afraid to share his personal experience to further explain something, even if it could be considered "controversial" (like his talking about and displaying his guns in his recent Waco video. ) He didn't show off his AR-15 to be edgy or look like some sort of badass (something I could see Moth doing.) He brought it out as a visual aid to illustrate his point.
While Moth seems to be actively trying to piss off potential new viewers (my guess is that he thinks it gives him edgelord points or some shit), Wendigoon is more friendly and welcoming in a way that feels genuine, which encourages new viewers to come back.
Moth tries so hard to fit a certain character type and I think it gets to him that Wendigoon is doing far better while barely even trying.