Don't conflate 'anti-vax' with 'anti-vax-mandate'. The two positions have entirely different scientific and moral bases. I would think the second group is also much larger.
https://www.merriam-webster.com/dictionary/anti-vaxxer
>Definition of anti-vaxxer
>: a person who opposes the use of vaccines or regulations mandating vaccination
It's been the definition since at least 2018 https://web.archive.org/web/20181125060933/https://www.merri...
https://web.archive.org/web/20210108224740/https://www.merri...
vs.
Calling this a meaningful change of its definition that "THEY" did is nothing more than pedantic anti-vaxx bullshit.