i think dropping dumbbells no matter how heavy (as this is relative) with disregard to your surroundings is poor attitude especially in a crowded gym.

dropping barbells from deadlifts especially when testing maxes is normal because you shouldn't worry about the eccentric phase of the lift.

other lifts such as the snatch will need to be dropped once the lift is completed but care should be taken to push the bar down to prevent it from bounding out of control. even oly platforms have rubber surfaces which does cause the barbell to bounce about.

Not all powerlifters look like couch potatoes mind you.

it's a changing room. deal with the fact that there will be people going about their business naked. ofcourse, if he's doing the 'i'm sexy and you know it' wiggle so blatantly, then it's time to give him a piece of your mind.

as for your deadlifts, HEAVY farmer walks using either dumbells or barbells. kettlebells too if they're available and heavy enough.

you might want to try to chalk up before you lift and see if that improves your grip. sometimes, the problem can be as simple as you're not gripping hard enough.