That would be trash talk. Leverage has nothing to do with it. Growth is not limited or halted. Belt's and wraps are usually worn for max lift's, not general workouts, though they can help support an injured area from time to time. Besides most guy's haven't a clue how to adjust a belt or apply a wrap. Gloves are worn by misinformed trainee's who may feel the need to protect the palms of the hand, for what ever reason.
Straps are designed to handle extra heavy loads. Where one would normally not be able to complete the exercise without them. Straps should not be used on every exercise, where you may depend too much on them rather than your grip. I disagree with people who might say to never use straps, you will weaken the grip. Straps can be a very helpful tool when trying for the last 2 or 3 very heavy rep's that really count. Your not going to make those reps if the grip gives out. I use straps on DL's (in all forms) and weighted chins (sometimes one arm) at certain training periods. Nylon straps work the best for me. The leather & heavy cotton one's tend to break, always at the wrong time, it seems. Good Luck.