Unsolicited advice is largely unwanted and unliked. I've been on both ends of this, as well as watched friends try to help people who just don't want to be helped. If you're careful and courteous, you can ask if they want tips, but you risk sounding pretentious. Nobody likes being bad at the game, and being told you are bad and that you need help (which is exactly what giving them pointers is) only adds fuel to the fire.
It's not a logical thing, it's an emotional thing. Being bad and being called bad feels bad. Be careful when you offer unsolicited advise!
Edit: I want to be clear that, while I'm blunt with my word usage of "bad," I don't intend to attach any "lesser player" baggage, I just mean not adept at Infinite Crisis (yet).