Mack is a MadTitan/Moonie alt, as in
imgflip.com/user/.M00NMAN.exe
imgflip.com/user/Silly_Memeus
imgflip.com/user/ChristianConservative
imgflip.com/user/ChristianNationalist
amongst others.
He used to upvote all of his alts, but slowed down because he kept getting busted on it. Plus maybe it finally dawned on him that it is an arduous waste of time to log in and out of accounts plus with different VPNs just to upvote his own comments for accounts that nobody knows about except himself. Since Mack makes the most points, he's focusing on that, as the others are more obscure.
And he does it within minutes of posting also, not just meme submissions, but comments as well. And it didn't matter the hour. Back in 2018, I caught him doing it at 3:00am EST. 5 upvotes per comment when nobody was about except for me, him and and another person or two who would not upvote him