The thing is, there are many places one can go to for advice on killing parasites with drugs, but few places that one can go to for an alternative treatment advice.
Another point is, that those that are self diagnosing, I would think, would want to start with the least dangerous methods, just in case their self diagnosis was wrong.
Zapping or using DE to get rid of possible parasites, is not going to harm you, even if your diagnosis is wrong, but taking pharmacuticals certainly will harm you is you don't actually have any parasites.