Actually, helmets in bull riding are becoming alot more popular. I've seen guys using helmets at all the rodeos I have been to in the last year. Alot of the younger guys are wearing them, I think in part because High School rodeo requires it and as guys move up the line they keep their helmets. I think it has a lot to due with person preferance. I don't use one but the two guys I travel with do. My decision came to down to two reasons. 1. I'm old school and I like cowboy hats.
2. I always thought that looking out of a helmet would make me think about getting hurt and thus hurt my mental game which is a huge part of bull riding. I'll also be the first to admit that I am a total idiot for not wearing one.
Frankly, I have never seen a bull rider make fun of another bull rider for wearing a helmet - that comes from the arm chair quarterbacks that never set foot in the arena. The riders I have spoken to all agree that anything that helps the protect the rider (within reason) is a good idea. Every time you climb into the chute you are flirting with disaster and busting your face isn't all that much fun, wearing a helmet doesn't make you any less of a man. It makes you a touch smarter than the rest of us.
Matt