A person who always sides with the same person, even when he knows that that person is in the wrong, he still sides with him/her, because the person knows he cannot win an argument with the one he always sides with
Mrs, Reynolds is so stale, she always sides with Patrice even though she knows I didn't do anything
To be Stale is to be in a Zen like state, for instance whilst having a hangover where the body is feeling sick, and the mind is not willing to do anything, hence zoning out, and being stale.