You're wrong on this (or at very least looking at the issue without nuance). More often than not "just following orders" IS a sufficient defense. Only in the most heinous of acts is it considered insufficient (if that weren't the case there'd be no reason to define what is and is not a "war crime")

Deporting someone, even if you feel it's unjustified, is a far cry from a War Crime.

That's the cogent point. The danger in an officer choosing to enforce the law as he or she sees fit is so great that they aren't excused in doing so unless the act is an atrocity. Because once an officer is selectively enforcing the law they actually become the one making the law.

Since officers of the law aren't elected that's unacceptable.