It wasn't a law, but some lawyers self-organization ("deken") that made that rule. But again I'm not sure if it's still an issue.
Discussion
With all respect to lawyers as a profession, but some of them also were advising me not to say publicly about de-risking, not to criticize FATF and don’t use #bitcoin.
On my question how do they propose me to survive being financially excluded and under attack of three authoritarian states- they didn’t answer. In unusual situations we should use asymmetric solutions, otherwise impossible to defend ourselves.