Absolutely! Great point, 1980. I believe this is called a "self enclosed hypothesis" -- an argument which cannot be disproven because its logic closes off any way to disprove it. For instance, to get away from politics for a second, some Christians believe the Earth is literally 6000 years old. If you point to evidence like fossils, or the age of the stars, or anything like that, the response is that God made fossils and stars to look as if they were really old, when in reality they were made just 6,000 years before. Of course, that claim can't be disproven, because any evidence that the earth is millions of years old can just be re-written as God making the world look older than it really is.
Without looking down on people who believe such things, I'd just say people should be really careful of falling in to self-enclosed belief systems like this. An easy way to see if you are stuck in a loop like this is to do the following: ask yourself, "What could someone show me that would make me change my mind about XXXX?" If the answer is "nothing could change my mind," then be very careful of your own conclusions. In my opinion, anyway.