Mary. There are any number of good beaches on St Martin. I stated my preference as Dawn having been to many. It would be correct to state that in your opinion "Orient is best" and would be helpful to the origonal poster to tell them why you feel that way.
As to" who would select a beach based on what the person next to them was wearing",
(or not wearing), many folks are not comfortable with topless or nude beaches and that would be a factor in their decision. Even in posting your quote I toned it down. Again , in my opinion, there was no need to be so confrontational with your comment.
Breeze, you will find Orient to be a fabulous beach as well. It is very popular with cruise passengers and with several ships in port can get somewhat crowded. The entire beach is not nude, but you will find topless women along the entire beach as this is quite common in European influenced beaches. There are facilities, drinks, food and rentals readily available along this beach.
As I like a less crowded beach, I prefer Dawn. Either would be a good choice for a day at the beach.