I've never really understood why people thought this. I mean as soon as you pick up Snake and play against someone, you'll immediately see that he's not a very campy character. Even on paper, Snake as a campy character doesn't make much sense either. His nikita has a slow start-up and is really only useful for edgeguarding aside, his grenades aren't nearly effective enough to keep away an opponent consistently without leaving himself wide open, and his C4 is rather useless unless used as an edgeguard or planted on an opponent.
On the other hand, he has an excellent grab game, being able to chain grab certain characters and/or combo into a planted C4, an excellent Oos option as well as a good GTFO jab option, great aerials if used properly, and of course the ability to plant C4 on the bodies of your opponent.
Unless baiting opponents also counts as camping. Then I'm completely wrong; that's something that Snake is very good at once he plants his C4.