[pc86]

Originally the anti-vaccine idiocy had its roots in the far left. It's found a home in the extremes of both ends of the spectrum. Pro-2A belief is not necessarily an extreme viewpoint in and of itself, but you'll certainly not find it in the extreme left. You will, however, find it in the moderate left and most of the right.

There's certainly some overlap but to imply that you're "very sure" they're the same group would make you very wrong.