Thanks for posting about this issue.
I find it frustrating that it is really not clear what issues one will get moderated for. The terms of service are open to interpretation. For example, it's not clear that telling someone you are going to give them a "red thumb" would be considered aggressive, but it is an offense that is moderated. Further, not being able to discuss moderation in these forums -- or reach admin or moderators to ask questions -- prevents people from really understanding what is, and is not, acceptable behavior so they can comply before getting moderated.
I was also moderated for having a discussion about whether table talk in Hand & Foot (a partnership card game) was against the TOS. We disagreed on this point and I asked if I should report the issue to get a ruling about whether it was an offense that could be moderated. Someone at the table reported me, and I was moderated for suggesting that as a solution to the conflict, even though my question was a sincere one about that as a way of getting a ruling from BGA admin/moderators, it was not meant as a threat.
I guess in your case, sephdar, you were supposed to know that "Peace to Ukraine" would be viewed as aggressive by a Russian player?
As far as your question, it is not automated. It is a human moderator sending you the warning.