Foundation was first published in 1942. It was first published as a novel in 1951, but it had previouosly appeared in 8 installments of Austounding Magazine between May 1942 and January 1950. So, it's seventy years old, of course it is dated. How much science fiction from 1942 isn't dated? And yes, it seems like science fiction from the 1950's, because it is from the 1940's. And yes, the female characters are lacking, but that's true of most science fiction from that era.
Asimov was an atheist, yes, but I've never heard of him being described as "rabid". Nevertheless, being offended by it doesn't mean he's a bad writer.