Girl at the gym approached me to tell me I had the nicest ass & skinniest waist in the gym. WTF is her problem?

Who the hell does she think she is, how dare she!. Surely this is inappropriate behaviour or is this an American cultural thing to approach strangers like this. Kinda creepied me out. I can't imagine commenting to another woman that she has a big set of funbags. Yes I wear yoga pants and a sports bra but I also wear a long t-shirt over them so she must have watched me changing in the women's lockeroom.

Updates
1 y
We not too long ago had the #metoo and Weinstein thing and so many people still think this behaviour is acceptable
Girl at the gym approached me to tell me I had the nicest ass & skinniest waist in the gym. WTF is her problem?
Post Opinion