My Friends Say The Darndest Things

I'm still wrapping my head around a conversation I had earlier today after overhearing a long-time friend of mine explain to her children that 'yes, the Jews are the people who killed Jesus'. She's the same friend who insists the U.S. never landed on the moon and that President Obama is a secret muslim... or something... it keeps shifting.
I've had a lot of crazy friends, stupid friends... friends who were just plain fucked up. Somehow I'm generally tolerant of it all... I know I'm no peach either.
These comments about the Jews don't even really rank of the general scale of crazy stuff I've heard come out of people's mouths and STILL I wanted to hang out with them.
I guess I'm just wondering how I keep ending up befriending people who I so thoroughly disagree with on such fundamental things.
I'm not inclined to put on some melodramatic display of outrage... everyone knows that there are plenty of fundamentalist Christians who feel that way about the Jewish people... that they're a means to an end (getting them to rebuild Israel so Jesus will come back and end the planet). I argued with her a bit... we didn't get too shouty about it... we know we don't agree on a whole lotta stuff and it's OK.
Is it OK? Am I doing some harm by not pitching a bigger fit over her nonsense?
Everyone has delusions and superstitions and dumb thinking.
Maybe it bugged me most because she was telling her kids that crap.

I'm not really sure what I'm trying to figure out here...