Whether Madmonkey's reasons were good or not is entirely subjective, but also irrelevant to his expulsion. At worst, he endangered the entire STA due to his spying actions; at best, if he was truly "just joking" then such immaturity is a liability that the STA cannot afford. If someone feels that espionage is truly justified, then they should follow that path, but either on their own, or with the informed backing of their friends. By going behind the STA's back, either seriously or in jest, Madmonkey left Tyga with no choice but to expel him.
Is it regrettable? No. Would I have done any different in Tyga's position? Hell no.