Honestly, it depends. I admit, I'm a selfish person, so I usually just concern myself with what's good/helpful/beneficial to me. So, if what's being snitched itself doesn't concern me, then I really don't give a fuck. It's obviously a different story if I'm the one being snitched, cause yea, i hate that (as does everyone).
Also, wanna say that I believe in being loyal to friends and everything but, again, I wouldn't needlessly put my future/life in jeopardy just to protect a friend for something he did on his own. For example, say you know your friend shot someone and then the police comes to interview you... do you lie, and take the risk of being charged with obstruction of justice/perjury or just snitch? tough decision.
Cause snitching would probably feel like betraying a friend, which in a sense it is, but imagine you going to jail for someone you didn't do, just cause you didn't want to be a rat?