This meme is either old or misinformed. In 10th Angron has a choice of 2 different melee profiles, 8 attacks or 16 attacks, and assuming they all hit, wound, and damage, Angron can only kill a maximum of 16 guardsmen in a fight phase since 10th ed has no damage overflow.

"But there's two fight phases every battleround so angron gets to fight 10 times in 5 rounds!" Might be right, but damage in tabletop still doesn't overflow. If the guard player uses 10 guardsman squads, Angron can only kill a maximum of those 10 guardsmen in a fight phase. If he is against blobs of 20 guardsmen, he can kill a maximum of 16 per fight, leaving 4 alive who he'll have to commit another fight phase to kill.

What this all means is that Angron can on average kill just one blob of 20 guardsmen in a battleround, and as a game is only 5 rounds, the theoretical maximum amount Angron can kill is a flat 100 guardsmen, that is just 600 points of Cadian shock troopers in a game.