> Months ago he was insisting that the people who had contracted COVID-19 and who had antibodies in their system may not need the vaccine. Now, we have a number of studies coming out to support that. But months ago that was "anti-vax" (employing the slanderous use of the term).

If you're claiming something that hasn't been demonstrated through peer-reviewed scientific research, then you're offering your opinion. If you present that opinion as a fact, then that's misinformation. I don't know what form his "insistence" had, but I've seen plenty of similar cases so far, and all of them have been from people pushing their own narratives, instead of informing people responsibly.

If you're pushing a narrative that implies that you shouldn't get vaccinated, then yes, that's "anti-vax".

> It's the stifling of legitimate public debate, the stifling of legitimate voices who find themselves in the minority.

Being in a minority does not absolve one of responsibility. If you're publishing your opinion, or if you're discussing your research before it's been peer-reviewed, you have the responsibility to make that clear, and even to point out that it does not agree with the current scientific consensus (if any exists).