When I heard this, i was shaken and deeply, and so upset while driving the subway though Stockholm (until i got good sleep and could wind down from it getting some distance). The thought, that a colleague driver is actively pulling in other colleagues and staff at my work place, into fighting a war which in reality is a meat grinder front - felt outrageous. And, too close for comfort. That something like that happens, or is allowed at a work place, is beyond me.
I mean the guy is a metro driver, but at the same time it appears to be Ok to do a lot of military missions in between (Officially, as a subway driver at the Metro you are not allowed to have any other jobs what so ever). He makes a lot of advertising on his Facebook page as well; for example his recent last trip to Ukraine (before what happened in Poltova though) dressed in military clothes. I do not believe for a moment that he is just a war entusiast. The rabbit hole runs deeper than that.
Is this union employment? What he is doing/saying may not be allowed at the workplace, as you said, and perhaps the employer just does not know? If there are a bunch of you seeing the same thing and it could be determined that the employer does not know, then they would likely take a dim view of it if made aware (strategically somehow).
In the end, you are there to make a living, not be recruited to war.