John obviously doesn't know what he's talking about, or he's bought into some of the oldest Urban Legends in the Military.
The food is pretty bland - but filling. There WILL be hot sauce, but in Boot Camp the idea is speed, and if you have time to lolly-gag and add hot sauce you must have too much time on your hands, and your meal may well be over as you are seasoning it.
Until Boot Camp is done, just eat what they give you and be happy with it. You can add flavor afterward.