TRUMP JR under investigation :), page-96

To help poor old sledg out, some believe vaccines work, some believe they make you sick, some believe they don't do anything.

They are all entitled to their belief. Which one is correct though?

Or am I assuming they are entitled to their beliefs, perhaps in the existing America that is no longer the case.

Is it a now a case of one must be right to be entitled to an opinion?

Or are people only entitled to an opinion if it agrees with ones own opinion, this seems to be a growing phenomenon so perhaps it's the answer.