“I really am puzzled how people would think it would be done.”
You would need a confederate who would see the moves broadcast online and signal back electronically what the computer says is your best move. After Carlsen’s tantrum the tournament went to a 15 minute broadcast delay which makes any possible cheating much much harder. Basically the only cheating option left is a player with an implanted computer chip, and I think they scan for those too.
Carlsen now needs to do two things: apologize, and consult a mental health expert.
I concur. Carlsen's behavior was shameful. The conduct of others at the top level of professional chess (i.e., Nakamura) surrounding this incident has hardly been much better. It would seem that everywhere one turns nowadays, it's Clown World.