The average 4th year US service member will probably have put up with massively more crap than the average college graduate. Which makes them tough in a specific way. That seems plausible enough :)

What I was objecting to

A) "Life is tough/ college isn't". Put in those terms, "Life is tough, X isn't" works for basically anything. And, I would argue, military service is closer to college (specific schedules, insulated from real world, the amount of time spent on PS/XBOX) than real life.

B) the tone that seems to indicate that the military has a monopoly in all types of toughness.