If Niemann comes in 8th place, the guy who misses out qualifying coming in 9th may think differently, especially if it’s close.
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?