How? First off the story from the movie was more like a rumor between the soldiers as to what happened, since apparently no one actually saw it.
assuming the gif is even true(because it was just one of the rumor flashbacks)
if the story they told about him in BoB is actually true.
Actually you are supposed to let them go. Everything else is a war crime. It´s kind of sick to see you defend such a thing. But just so you can feel how distasteful this is: I´m sure you heard of the Malmedy massacre Kampfgruppe Peiper committed? That was also because they were supposed to advance fast. The prisoners were a burden. Doesn´t make it any less perverted. Everyone who does such a thing to soldiers deserves to be hung from the next tree, be it the murderers from Malmedy or Lt. Speirs. For the latter we could consider the benefit of doubt of course. Yet the gif depicting that supposed crime... him shooting unarmed guys is still shit.
Was he supposed to hand cuff them, and leave them there with no one watching them? Was he supposed to let them go?
a gif, that didn't even show what you're talking aboutThat is exactly the scene where he shoots the POWs. You might notice the kneeling German.
https://www.youtube.com/watch?v=FcZl32NnIrs