It's a matter of choice. For a democratic republic, why are there those who resent men choosing speedos? I always wear speedos (I'm actually quite flattering - according to my wife and lady friends - so it helps) and it's entirely because for a better tan and better swim - yes, I don't mind the attention either.
First, let people wear whatever they like. It's as much their holiday as it is yours.
Second, can you imagine obese passengers placed on a food quota on their cruise because they're fat?
Finally, don't interfer with my choice of speedos and I won't interfer with your choice (or is it amount) of food!