[jVinc]

But why though?

Lets assume just for the sake of argument that Magnus has insider information from chess.com making him 98% certain that Niemann is cheating.

Why would he hand him a game that's going to be watched worldwide, where Magnus has nothing to win. Since if he wins we really still don't know anything one way or the other. But he also has everything to lose. If Hans is cheating and manages to pull off something again, then Magnus is cripeling his own reputation.

Magnus seems to be doing the right thing here, which is voicing his concerns, refusing to play him, and asking Niemann for permission to speak on the matter fully. Niemann is doing what you'd expect of a cheater, which is to stay quiet, dismiss the discussions, having difficulty explaining his plays, and pretty much just holding back from letting chess.com or Magnus divulge what information they have from the inside of his bans.