Really no problem that you ask. That's what steemit is made for...
No, there is no relation to any other social or political purpose at all.
I do not specially enjoy doing it - I just don't do any effort to hide my nipples by a bra or an extra layer of clothing. If I like to wear a top and you can see my nipples sticking out I know the guys will not complain at all 😉 and for me it's simple and comfortable 😊