Because you look better with makeup. People like people that look nice and put together. It shows you care about your appearance and put effort into looking nice. You might think you look better without makeup, but a little bit of makeup makes anyone look better
just because you are a woman it doesn't mean that you HAVE to wear makeup. You don't have to go for the doll face. You can keep it minimal and just use mascara to open up you eyes so you don't look tired and some blush for those healthy rosey cheeks and a lipgloss and you are good to go it takes a couple of min to apply and you don't have to touch it up through out the day or worry that you look too made up
"And because I look polish(ed) and professional with some make-up on" - you just answered your own question. You look good and in keeping with your environment. You look like you've put some effort in, and people like that.