Why do players think they can do this when not in a hand?

[MicroBob]

The fact that they THINK they know every single rule is their fault. Because they should know that they don't.

But the fact that they don't know every single rule is something that I think should be addressed by poker-rooms.
They are less likely to learn the rules as quickly otherwise.

Lots of n00bs playing poker who just don't know any rules at all and I think they should be elaborated just a bit more so that they are given at least SOME clue.

Some of these that I think can be posted might include elaborating on the 'one player per hand' rule to specifically state that if you aren't in the hand you are not allowed to comment on the hand in progress nor are you allowed to discuss the cards that you mucked because that knowledge could influence the other players.

Stuff like that.