I could imagine that for the times it was made in, his behaviour may have been even more extreme than it would be today. As for his sexual attraction, I guess it is because he just is the way he is, while the others are always pretending. And the other guys in the film don't look much better on the outside, as far as I could tell. Anyway it's Michel Simon - that may have been enough reason 
Don't have a particular interest to see a remake, but it could be interesting if somebody would try to make this film in today's France. I wonder if it would be as positive...
Do you by chance happen to remember the beginning of the film? I missed the first five minutes (or so), and would like to know if there was anything essential going on. I entered, just when Boudu lost his dog in the park (saw him still in a last frame).