I did an 11-hour ride last week in a pair of soft, baggy trousers and a cotton T-shirt. Only 100km or so - I'm very slow now that I'm old.
But I'm always astonished, and a little disgusted, at the sneers at people who choose to wear Lycra/Spandex. I would not dream of sneering at golfers for their odd dress, or at tennis or cricket or baseball or basketball players, all of whom have their own choice of dress.
I think the sneers at cyclists and their dress are an expression of class distinction - the kind of Andy Capp stuff that some people used to find funny when the targets were from Africa or the Caribbean.
As for cyclists and red lights, every video-backed study I've read says drivers break the lights more.