I wear the clothes I choose for riding to suit me and my needs, not the perceptions of others on the roadway, regardless of conveyance. I typically wear normal street clothes with bike shorts (and SPD shoes if the bike's pedals call for it), and I'm as comfortable as I would be in cycling-specific kit, even at 35° or 105°(F). Due to the wonders of technology and the market, nearly all the advanced fabrics used in cycling clothes are generally available in street clothes. My choice, and far better than the choices available 40 years ago.

Edit: But if riders want to wear cycling-specific clothing, I have absolutely no problem with that either. Let everyone choose what suits them best.