A guy at work I got to know claimed to be a Jewish atheist. He went to Temple on Saturday. He said it was Jewish, but not religious, at all. It celebrated heritage, no religion, no war, etc. I thought that would be hard to do.
I googled it and he was correct, a secular Jewish temple.
The wife's friends claim to be Jewish but don't participate at all and haven't for eons. My buddy who owned the wine shop was Jewish and didn't attend anything but his wife converted and he would celebrate Hannukah etc. He made those potato cake thingees in the back of his shop a few times, they are pretty tasty.
I still chat with him from time to time. Our next door neighbors were Jewish but didn't attend anything, I don't think the wife converted. He was my MD. I never knew of a reason to be against Jews based on the ones I've known. Of course, I'm pretty easy going, I even like some French.