To be honest with you; I am not sure why pressing jump after shooting "makes you skilled" because that's what you're implying with the term good sniper in that post. I thought that aim decided the quality of a sniper; not if he knew that he could jump to cancel his scope earlier and other snipers didn't. I say this because I knew that I could jump; but most other snipers I met didn't do this. That's not skill; that's just me knowing a trick they didn't know. For them it looked like their enemy was just being frantic or something. Sniper being the most vulnerable class in the game is debatable because it always depends on the situation at hand.
That's what it was, just a trick. I don't see why make such a fuss over it, it's not like it saved you each time. Yeah, sometimes you get shot on the neck instead of the head, but most of the times (at least with me) it doesn't really matter, jumping doesn't move you so much to avoid the hit.