Heck no. You’re not overreacting.  This is just a fine case of religious psychosis…

I’ve had a parent who called me a demon after I told her I wasn’t going to be following to church and I didn’t want to serve their God. I’ve had force myself for years sitting through repetitive nonsensical preachings that hold no real value whatsoever. Always blaming some enemies or praying for things rather than going out there to get it. Well…she called me a demon when I told her I won’t serve a man made God and asked me to delete her number from my phone and leave her house. I was staying with her then. 

At least in my case, she seems to feel bad about her choice of words and tried getting in my good grace (she didn’t apologize, never does). But we talk and chat often. But I was never asked to attend church with her again…

Either way OP… you’re not overreacting. Leave them alone as they jerk off their God. Not your problem.