Surely there is middle ground between "all soldiers do it" and "no soldier except Talian ever done it".
While no army is composed of highly emphatic saints, armies differ in their general level of violence toward non-combatants, cruelty, how pleasurable they perceive killing and so on and so forth. Ideology and reward system have to do a lot with how army or specific unit behaves.
Sure, I just don't really subscribe to the notion that "they're brown so they must be evil". The data I have right now is "these soldiers were taking killing lightly" and, if I'm going to generalize from the data point, I'll generalize to "all soldiers take killing lightly" rather than "the Taliban specifically take killing lightly", since that makes an additional assumption that the Taliban are special.
Both nazi and communists took killing lightly or as manly honorable duty. They were German and Russians respectively. They believed they are doing right thing with no ambiguity. They had fun with it. They were more violent as western armies toward non combatants.
The original claim was about this particular unit. Assumption that they are representative of all brown people is wrong. Plenty of brown don't subscribe to this ideology.
Armies indoctrinate and socialize people differently. Implying racism on part of people who don't extrapolate one unit of one army behavior to all of them is not great tactic.