This is a great post that illustrates an important point. Whenever you make a statement, you're bringing a large number of beliefs along with you.

Stating that "the car is red" brings along your beliefs of red, car, and possibly is. Its a good bet that most people have very similar beliefs about the meaning of 'red' and 'car', so it's immediately clear what your meaning is.

But with a statement like "God exists" or "Islam is a religion of peace", you're dragging along with you a huge number of beliefs, many of which you might not be aware of. And so an argument like that will go round and round until its made explicit what beliefs you're talking about.

One of the main strengths of rationality, in my mind, is that it forces you to consider that hierarchy of belief that sits below every thought and statement.