I suspect most embassy staff are -- like the ones from Western nations -- generally pretty liberal, and probably secretly fairly supportive of this.
I just heard an interview with a journalist, Jolyon Naegele, a Western correspondent in Czechoslovakia in the 80s (who worked for Radio Free Europe). He talked about how Czechoslovak secret services bothered him (often in a very crude, stupid ways) and also how they, in some sense, were afraid of him, since they assumed that he is a foreign agent. The assumption came from the fact that all the Czechoslovak foreign correspondents in the West actually _were_ agents of secret services.
My point is, you cannot generalize the systemic features of Western liberal democracies to authoritarian countries.
So I would be surprised if this is not true for diplomats as well. Most of them, if not all, are probably operatives of Belarusian secret services, and they probably have mostly conservative-authoritarian values.