I don't really understand the allegation put forward in the programme. I see that Protelion is suspect but why would this reflect on Cyber-Sicherheitsrat Deutschland e.V.?
That all would be ok, if not a couple of huge companies are member of this society. So, if you are in cyber security, this is a little bit too fishy.
This would make sense as an answer, if Schönbohm had a connection with Protelion (other than indirectly through CSRD e.V.). Are you asserting that that is the case?
Otherwise, the links in my mind at the moment are:
KGB — Infotecs — Protelion ... CSRD e.V. — Schönbohm — BSI
where the link "..." is not obviously suspicious (although I'm not saying evidence couldn't be adduced to make it suspicious).