We can’t make that assumption either way, especially without an sort of trail to hear his response (which would of course be through the lens of time, anyway), which you rightfully note. However, just because someone might or might not have been actively complicit in a crime, that doesn’t mean we don’t go through a trial of some sort. The reality is that (whether he was enthusiastic or not, forced or not) he was involved in a crime against humanity here. Should we really just ignore that?
Are you saying 19 year olds aren’t responsible for their actions? or that there weren’t choices that people could make in the midst of this? Given the reality of the occupation of Poland - that they did not have a collaborating government, and had a relatively high level of resistance and backlash to that resistance, with thousands being killed for refusing to go along - there might be something to your argument here - but then again, “I was just following orders” has not been an excuse in many other cases, so why is this one different? I’d also offer that there was a very active partisan movement that many young people were a part of during the war. People had choices to make, and of course they were hard choices to make, and many went along with the occupation out of self-preservation. Others (many others) resisted or sat things out as quietly as they could.
But once again, there has been no actual case here, just a deportation order, which has yet to be acted upon. the issue at hand is that while many others who are here without documentation are being deported, often to places where there is a rather high chance that they will be killed RIGHT NOW TODAY. This has already happened to children who had come north without their parents and were sent back to be killed by the criminals they were fleeing in the first place. Sending this asshole back to Europe isn’t likely to result in him being brutally murdered in his sleep. He might be put on trial (though that seems unlikely in Poland at this point) for his participation in the holocaust (whether coerced or not).