I disagree, an opinion is a statement of what you think about a subject. A vote is an action. In this context a vote gives power to who you are voting for to determine the rules of the network.
It's the the difference between saying "I think that you should be able to hunt bears" and actually giving someone a gun that they can use to hunt a bear.
Having the right to free speech does not exclude you from the responsibility. For example, you have the right to say whatever you want about someone in a public forum but if what you say is untrue and damages their reputation you can suffer legal repercussions.
Freedom of speech is not freedom from consequences.
You are free to disagree but a vote is speech. Your agreement is irrelevant to that legal topic.
PS: for the sake of clarity, I don't agree with actions by Justin & clan either.
A vote for a witness is more than just speech. It changes the witness positions. It's an action not just an expression of an opinion. The examples I gave are just analogies to ilustrate the difference between the two.