I have a friend who's gone off the deep end in the past year (like so many others).

He freely admits that he doesn't believe the vaccine is bad, and might even be good. His sole reason for not taking it is, and I quote, "because they want me to." In other words, simple spite.

We're not talking about a teenager here, but a successful man in his 60's who is probably the single most well-read person I know.

You see no value in the instinct to resist conformity? All major social and scientific progress has been made by someone with that kind of mindset.

You could argue that it's misplaced in this case, but that's already a more charitable interpretation of anti-conformists that will serve you better than just saying they've "gone off the deep end".