I don't think anyone is confused, but rather surprised for being so under weight. I'm sure those cats are Asians

with super fast metabolism. 5'9'' at 120-130 lbs is probably what most guys back at home weigh. When I was there and hitting the gym, I was one of the biggest guys there

I bought a couple of shirts too, had to rock an XL which fit like a small here.
There are definitely small guys that are deadly, word to Bruce Lee.
If my guy is 5'9'' at 120-130 lbs killing P90X, I'm sure he's in top shape. No one is doubting that. We're just critiquing since he wants to get bigger.