And we're all agreeing with you. We're simply saying that 'I Con the gangers into letting us pass' is just as valid as 'I put a short burst into middle ganger'. If you succeed (make your roll), there are certain consequences; if you fail (miss your roll) there are certain consequences. This applies no matter what SKILL you happen to be using, and should at worst gain the player no RP bonuses or penalties. (Penalties should come when you offer them something blatantly wrong - or even subtly wrong.) Penalizing a guy who just hasn't the RL chops really IS like penalizing the guy who doesn't know enough to say that he's gonna take in that breath, let half of it out, and gently squeeze, not pull, the trigger.
In regards to the question laid out by the OP, though, your GM - and the other players!! - should help you out in trying to get some of those RP bonuses. "Well, Con means you're gonna scam them or something - a bribe, faking like you belong there, or what?" Your table should be helping you out, especially if some of them ARE better socially. And in helping you out, they increase your chance to succeed, and thus the team's chance to succeed.