At the point where the Filthful and Disgraceful Slavebugger make it mandatory for the regular jokehovians to take it, that is when they should be required to take it or they are hypocrites. And if they ban it, there had better be a good reason--aside from it might contain blood or just to clash with the government.
And yes, I can think of plenty of good reasons not to take it. However, everyone should do unbiased research on it, and make their own decisions. (And having the companies not forthcoming with the truth, and shielded from liability if something goes wrong is a major reason why I refuse to take it at all). If, after you do your research on it, you feel the benefits outweigh the costs and drawbacks, by all means take it.