No one is saying you cannot have those thoughts, no one is saying you cannot use your free speech to spread those views. What people are saying is don't be surprised if people don't want to associate with you. You seem to have a odd view of freedom of speech, you seem to think it means there aren't consequences to your speech.
If you deny objective evidence, and hide behind it's my opinion man, you are no different than someone who denies the holocaust, 9/11 truther, terrorists are coming through our southern border, etc. I don't have time for you, I don't want to associate with you, and guess what that is my right.