It would be fine to disagree with an atheist by saying why the theist believes in god and vice versa. But once the two people disagree, IMO, it is time to move on. Bringing in other people not part of the conversation, or arguing what scientists do or not do at work are red herrings or, simply, extended Gish gallops.
A person believes or they don’t. A person talks about it or they don’t.
That’s my opinion anyways.