So? Snake's punches didn't cause any damage to Gray Fox, at the very best he caused him pain with his punches. People in life have survived falling off of buildings and getting hit by cars, that doesn't mean that I have impressive strength because I'm able to hurt them with punches
Hell in MGS4 Vamp was able to stab Raiden with regular knives
Raiden doesn't swing his sword with enough force to rip someone's arm off either.
http://www.youtube.com/watch?v=YzLQMO0W9U8
Watch at 3:20
Raiden threw his sword at Vamp, he dodged it and the sword hits the Gecko behind him, the sword barely penetrates the Gecko's shell.
If you want a better example watch their fight on top of Rex, Raiden manages to hit Vamp a few times, if Raiden truly had class 100 strength, hell if he was as strong as Spiderman he would of sent Vamp flying in the other direction.
Now to be fair before that Vamp did manage to jump from the ground to the top of Rex, however Rex was it's side so I'd guess it's maybe a 20 foot jump, it's also possible that since Vamp was wearing the same tech that let the FROGS cling to walls, he might of been using the tech that let them jump high into the air in the first place..but if not at the very best it shows Vamp having strength in the peak-enhanced range since there are a few peak humans or enhanced that can jump 15-20 feet in the air. It doesn't help Snake though since at the best he put a peak human in a chokehold.