From a sports psychology point of view , silence would be preferential to moaning or abuse.
Better still , praise the effort and just give unwavering support.
It depends on how you define “moaning” someone sighing is neither moaning or abuse. Why would anyone play a sport in silence? Unless of course you put chess as a sport. Football is, and always be, a very emotion filled sport Bill Shankly thought so and we have a stand named after him.
It is never going to happen where the only emotion shown is a cheer and it’s stupid and unreasonable to expect that. I will say again abuse has no part to play at all that is something different and you should separate what you perceive as moaning and abuse.