i think it has a higher impact when someone you already like aka a crush, girlfriend boyfriend wife husband etc is wearing it, sometimes red just suits their skincolor and haircolor and they look more attractive, red is known to make you happy as well and makes your pupils dilate since its the brightest in color spectrum
however it doesn't mean that any stranger on the street wearing red is automatically attractive, I think it only pertains those you already have feelings for
i know because my crush wore this red hoodie one time to school and holy moly he looked so handom and sexy. and I've randomly wore red and my friends said it brought out my brown eyes
I think red is just a striking color. It's hard not to look at something that is red. It's actually a color used in films a lot, so the audience can stay focused. For instance, "The Sixth Sense" and "American Beauty" they both used red to get the audience to focus.
I don't think it is a girls' color either. This shirt looks great on him - link
The correlation between the color red and sexual attraction is merely anecdotal. Anything you've read about red attracting people is just a puff piece article by some flailing journalist recycling the same crap.
Scent, as opposed to sight, has a much higher degree of correlation as well as physiological attraction. The reason being that the molecules that you smell are directly entering your body and brain, whereas with sight, there is interpretation of volume, depth, shape, etc.