One really devious tactic of argument is to take the argument away from the merits of what's in question, and turn it into a conflict of worldviews. Take homoeopathy, for example, that instead of arguing that homoeopathy is reasonable, it would be to take the opponents of homoeopathy as being materialists and that the criticisms of homoeopathy only work under that commitment to materialism. The tactic, in effect, is saying that the proponent and the sceptic are working in different realities, and thus the debate shifts to the relative merits of the worldviews rather than the topic at hand. In other words, any unreasonableness of a given proposition can be hidden behind the alleged absurdity of the sceptic's prior commitments.
And that pesky problem that the presupposition may be a conclusion rather than a prior commitment? That's letting accuracy get in the way of apologetics.