actually...

both the way we vaccinate as well as the theory of evolution have changed over the years.. neither was born 'perfect' with no need to ever question or try to improve on. Creationists might take things a bit too far, but there still is not a complete concencus on evolution by science (not if the general theory holds, but some of the details).. there's still quite a few things we're trying to figure out :)

Homeopathy is different as it is based on an outright lie, that a lack of something in water can cure things which are unrelated (but, by all means, let is disprove it with science rather than just scoffing at it repeatedly :)