I’m generally considered a millennial (born in 1985), and even I find it a bit odd what manner of attire has become acceptable in public. I’m generally of the mindset that you’re ok as long as you’re not harming anyone else, but we still have a civilized society where people adhere to certain standards of appearance in certain places. Too many people seem to treat public spaces as their living room. I don’t think it’s unreasonable to expect you to cover up and not get your hair and sweat all over the place in an upscale hotel lounge.

Also, I can’t help but think if this had been in the U.S., the responses would be more along the lines of “typical narcissistic Americans”, but since it’s Paris, it gets chalked up to “eccentricity”.