In our FAQ post: How does a new user get started on Hinduism SE?, we have following suggestion:
Avoid asking cross religion questions, I am just highlighting this out in bold because we want to avoid religion wars here, don't compare any other religion with Hinduism, stick to the topic, I would not post any examples for this, I hope people understand. Don't compare religions on good/bad parts, don't post questions if you've heard some cross religion rumors ...
So, as per this FAQ, we are supposed not to allow cross religions questions or questions that compares religions. But we have a tag for other-religions through which we sometimes compares the concepts of religions.
I think we need to determine the scope for the other/cross religion questions. Provide your feedback in the answer: how much of cross-religion questions we should allow or which types of questions should be allowed and which not.