Ballet has many body movements, and the beauty of ballet is the beauty of that kind of body. So in order to highlight this beauty, most ballet costumes, especially men's wear, are tight.

In Europe, the prominence of body organs should be a habit. This is the difference between eastern and western cultures. Therefore, oriental art is mostly reserved. Western art is mostly naked and open.

This can be seen in some oil paintings and sculptures.

It's just my personal understanding. You can also find more information in this respect.