That I know, girls with bare legs but a nice professional suit, a knee - or a bit above - skirt, have nothing wrong or unprofessional, especially in we are in summer and there are 1000 degrees outside

it's just human. You can be as unprofessional even with fully covered legs and with pants. A pair of black thick heeled low cut heels or slingbacks are also perfectly appropriate.
I don't think it's unprofessional to show bareleg even considering many men has a fetish for hoses, so that can be just an excuse, and it actually ought to be quite the opposite if the point was appearing too much daring and flaunting.
As a boy, though, i wonder how is it more comfortable for your feet. Yes your legs get aired, but along with them your also bare your feet, so are they really more comfortable than when some fabric is between them and the shoe to minimize friction?
In summer I try to go sockless with loafers and shorts, but I always end up putting on a pair of dark ankle socks just for comfort, at least most of the time (mostly in the evening cause I don't want sock tan), but as a boy my ankles don't matter so much.