What do you mean, "incorrect"? Matching a concept generates connotational inferences, some of which are true, while others don't hold. If the weight of such incorrect inferences is great enough, using that category becomes misleading, in which case it's best to avoid. Just form a new category, and attach the attributes that do fit, without attaching those that don't.

If you are still compelled to make analogies with existing categories that poorly match, point out specific inferences that you are considering in forming an analogy. For example, don't just say "Is cryonics like a religion?", but "Cryonics promises immortality (just as many religions do); does it follow that its claims are factually incorrect (just as religions' claims are)?" Notice that the inference is only suggested by the analogy, but it's hard to make any actual use of it to establish the claim's validity.

Cryonics can both be a good idea and pattern match onto something religious.

People want immortality. Religions have exploited this fact by promising immortality to converts. Then a plausible scheme for immortality comes along and it looks like a religion.