I think most of us find it interesting, harmless and even quite enjoyable to peek at others in the locker rooms?? I admit that I tend to like to see who is circumcised, who is big/small, who is shaved or trimmed, what type & color underwear guys are wearing, how bold/shy they are, how their cock fits & looks when its put into a pair of briefs, how they react if they catch you looking, etc. Even when someone sees you glancing at their penis I don't think there is much of a problem. We all know that pretty much all of us has a look at least sometimes. Often it is our peripheral vision that tells us whether to consciously look or not, flagging anything deserving attention, overlooking the more routine cocks/pubes/underwear, etc. I've found that my friends either admit they look at others, or if they say they don't, I like to test them out. For instance, I said to one such denying friend that he was the only one in our soccer team to be shaved .. no, he'd say, Gary & Stewart are too. I'd say he and I were the only ones circumcised .. no, he'd say, what about Tony, Pete and Andy. I could similarly state something about underwear or cock size, and a similarly comprehensive account would come back.
If you deny looking yourself, test yourself immediately after your next locker room encounter & I bet you find you can recall lots of details for at least a handful of the guys who were near you, if you tried! There's no shame in it, & it doesn't mean you're not hetero.
Apart from the curiosity, I am definitely influenced by others in terms of trimming my pubes, styles of underwear, and the group etiquette of what is too much or too little modesty