Persian Jews?!?!

So, I'm finally watching Bravos "shahs of sunset" and I'm trying to catch up on the story lines. 

Wow. I'm a little overwhelmed. 

And confused....

They're all Iranian - but some are Jewish!?  I thought Iran hated Israel?  But they're celebrating rosh h'shana, and having people convert to Judaism!! 

Huh!?!?

I mean- that's awesome!  But can someone please explain this to me because I've always heard the complete and total opposite. 

Thank god for google....