Niemann's rating is 2688 - #8 out of 16 players.
So, yeah, maybe it is unfair for Carlsen to toss him 3 free qualifying points.
On the other hand, what should Carlsen do if he thinks Niemann cheated in his previous game? Stay silent and do nothing, since he cannot prove it?
Chess.com banned Hans for what they say is repeated cheating recently, but they don’t release any evidence saying that they can’t reveal their anti-cheating algorithms. (Sounds like the FBI and Merrick Garland). Chess.com is also engaged in negotiations with Magnus about some deal so I would encourage Hans to get a shark legal team. A European women’s Grandmaster threatened to sue them over a cheating allegation and chess.com backed down, but that was a while ago.
There is zero evidence that Niemann ever cheated in an over-the-board game. Magnus Carlsen, the World Chess Champion, unfortunately is a paranoid jerk.