I'm no laywer as well, but with luck I soon will be
With BEFORE I meant that a party banning procedure is like a criminal trial with the result (ban or no ban) at the end, while banning an association under Vereinsrecht is a simple administrative procedure which can be cancelled afterwards, by a Nichtigkeitsklage (nullifying action) against the governmental agency who issued the ban.
The problem with the constitution and legal practice is that the constitution is mostly a piece of paper. Certainly, everybody quotes it, but in practice, common law is more important in interpreting the statutes. Only when you run out of precedents, you use the constitution.
And regarding the anti-constitutional nature of scientology. First "politically no more in doubt" is something totally different than "legally proven", as I said, in dubio pro reo applies here, sadly.
Second, german common law regarding anti-constitutional behaviour state that simple anticonstitutional ideology is not sufficient for a ban.
There has to be an "aggressiv-kämpferische Grundhaltung" (aggressive basic attitude), in regards to how the association/party tries to attain its goals.
If for simple anticonstitutionalism, monarchist parties would be banned for violating the republican principle in Art. 20 III, but since they're nothing more than nostalgia clubs and not actively trying to bring the Hohenzollerns back via a military coup, they are allowed (and of course because they're small and harmless
).
So of the three reasons to be banned:
Anticonstitutionalism (-) the agressiveness is basically missing. That is exactly what went wrong in the NPD trial. The defence successfully argued that it was the Verfassungsschutz moles who had instigated that agressive spirit. And since HUMINT is about the only way to prove such aggressiveness, the defence could claim the same here if BvV has moles in Scientology and discredit their testimony.
Anti-Peaceful coexistens (-) this only applies to neo nazis and the likes
Instigating criminal behaviour:
That is the interesting part. It really all comes down to consent. If the state can find witnesses subjected to anything they did not consent to, Scientology could be in trouble.
Problem is, consent can be far reaching, as I said, almost anything except your life and your basic human dignity (Article 1 constitution) can be consented away, at least among private parties. So if they sent somebody into a torture camp and can prove he consented to it, they can actually get away with it within certain limits.
Anyway, the chase is simply not strong enough, so I don't think it would be prudent to ban them.
The political ramifications of failure far outweigh the potential gain.
Especially since every failed ban makes that weapon more blunt. You see that in the whole business with neo nazi demonstrations. Every time they announce a demonstration, they get banned, they go to the court with a list of precedents as long as the courtroom and get it allowed, adding another precedent to that list.