/shrug
There are other, seemingly popular, items to believe in that can more readily mark you an imbecile, i think... Nostradamus was, without a doubt, a brilliant man. The myths surrounding him and his life just expand on that idea - where as there are plenty of things that people fervently claim to believe in (man didn't land on the moon, human pollution has no effect on our environment, etc) that have even less sensible backing than the myths surrounding Nostradamus, imho.
Personally, I think he was just a social commentator that spoke in vague verse... leaving people to translate it all as they see fit... the guy ardently shunned the title "prophet" throughout his life... he considered himself a historian.
Lots of mythos surrounding the guy's life, for sure... my favorite being that his body was exhumed during the French Revolution and found to have a medallion around his neck with the same year of his exhumation... right before the guy that exhumed him got killed by a stray bullet from a near-by battle. I'm sure it's all bullshit, but still interesting bullshit.
Just goes to show the guy had a profound affect on people in his time.