He is odd, to say the least. Nothing wrong with being odd, but that is what he is, and from what I can tell, he doesn't care.
If you are offended by the notion that others see him as odd/weird/strange, then the problem is yours and yours alone, because he doesn't seem to care. Perhaps you should do some navel gazing, because he has...and he has found mushrooms! (Sorry, couldn't resist)