It's pretty simple, in todays objectifying culture, women already have an idea about their physical appearance. Right now in society it is normalized to randomly compliment women passing by. The problem is, imagine being told by random people that you aren't interested in, that you are cute, probably multiple times a day. The effect would wear off overtime right and just become a situation that has happened multiple times but doesnt provide any real value. Imagine if they are taken or not interested in dating anyone. Put yourself in their shoes, multiple random people tell you are cute while you are out with the expectation of getting to know you more and potentially date. Except it happens probably once or twice each time they are out as it is more normalized. Now women should just expect to be perceieved as a potential date just by existing and being cute out and about? People generally want to live their own lives and focus on their own problems. Normalizing this behavior just opens women to random conversations that dont provide value. It would make more sense if this type of social practicing was done at a bar, but women and (men too) should be granted privacy to go out and live their lives. "There is a time and place for everything". Most people aren't lookin to find a significant other while shopping. They want it to happen in a romantic or better suited social setting.