Sorry to use that word. It is from another context, but you are right to point out that in this context it is a terrible word to use.

This is too much to discuss here. It has to do with epistemology and theories of relativism that most people don't really care about. I'm not a relativist. I do think some views are closer to the truth and some are off. That is all I meant by saying not all opinions are equal. You can say the moon is made of cheese but is that equal to saying it is a satellite of Earth without an atmosphere composed of dust and minerals?