"Whose American Cultural norms?"
Those of the majority of the passengers, I suppose.
"Are you planning on enforcing American cultural norms on foreign beaches when
you go on the excursions?"
When in Rome...
"I live in South Florida(the english speaking part) and thongs are acceptable..."
I live on North Florida, and most respectable people here don't wear them.
I was just looking at the rules for a water park that's about an hour away from where I live (I go there to "play" regularly during the summer). One of the rules, according to their Web site, is:
Traditional swimwear is required. No denim/blue jeans allowed. No provocative, thong or G-string swimsuits, clothing with rivets, buckles, belts or metal ornaments. No long pants or cut-off shorts. No oversized or baggy clothing that cannot remain at or above the waistline without a belt or other support.
This doesn't seem to create an undue burden, to me. Don't know why such rules might not also apply on a ship.
"I was 12 when I was travelling in france and germany..."
But the ship isn't France and Germany.
Here's the way I look at it... No one will be offended if you DON'T wear a thong. However, quite a few people may be offended if you DO wear one. It's no large inconvenience to cover that butt up, so why shouldn't we do it out of consideration for others on the ship?
The attitude I'm seeing (and I'm not talking specifically about you) seems to be mostly that of selfishness. If you're comfortable in a thong, wear one--who cares if it bugs other people? Well, I think we *should* care if our actions bug other people, at least as much as we reasonably can. As I said before, I'm most comfortable with no clothes on whatsoever. That doesn't make it appropriate on a ship, though.