Knowing and understanding a politician's religion is very important to me, and it think it should be important to everybody. I know I am probably more sensitive about it than non-ex-JWs, but I wish other people paid for attention to it.
A person's religious beliefs naturally influence a person's decision making about a lot of things, and it is a great way to tell what their world view is.
For example, Trump made it very clear that he was against muslims and wanted a muslim ban when he was campaigning. I am guessing there were people who disagree on that issue, but voted for him anyway. For me, it would be a deal breaker. I think it should be for anybody.