It’s like how people are okay being shirtless around a pool but it suddenly becomes super awkward if you’re not around a pool. The other thing is that 98% of the people in the restroom aren’t actively trying to look at your dick, just like you aren’t trying to look at theirs. The only time it’s uncomfortable is if the once in a blue moon creep tries to gawk at ur dick, but even then u just zip up and leave, what’s the big deal?