A great point. The same people decrying a vaccine that has been safely administered to nearly a billion people at this point and extensively studied will be the first ones to try all sorts of untested homeopathic and "alternative" nonsense.
We can do better than guilt by association. It's a very weak argument, and turns more people away from potential vaccination. In fact insulting the remaining audience is worse than preaching to the choir, because it even turns away people who were previously 100% on one's side.