Call it what you will, but the ability of dissenting voices to be heard is the basis of free speech, and also integral to the pursuit of science. Blind trust in authorities is anti-science, and suppression of dissenting views is also anti-science. Those in position of authority like to cast out all who have opposing views as lunatics, but that isn't true. When those in position of authority lie to feather their own nests and cement their power, the truth will be found among the dissidents.

Specifically to Kennedy, in his congressional hearings I've watched does not present himself as a doctor or a scientist, and also not anti-science. His main thrust appears to be that there are a great many problems in the status quo, the "authority" scientists and institutions don't have any reasonable explanations for them, and there are other scientists that are not financially entangled in the status quo that have theories that look to be worth pursuing. That is pro-science in the meaning of exploring the world in pursuit of truth. He is trained as a lawyer, and it is within his profession to be leading inquiries into intent and motivations of various parties in a dispute.

The characterization of him as anti-vax is a slur, and greatly simplified from what he actual advocates.