A good way to look at it is that any opposition is conviently labeled as "evil" by the narrative. The "evil" label means they cannot be good. They are non-people, and the only just response is to murder them. In dnd, virtually ALL problems and conflicts are solved via violence and murder. Yes, you might have a diplomatic plot point, but 99% of all disagreements in dnd are solved by murdering the other side. We say "fighting evil", and they are evil because we need something to murder, and its ok to murder and rob evil "creatures".
Consider the idea of "bad guy" or "creatures". When was the last time you kicked down a door and murdered 5 women? Bet it never happens. When was the last time you kicked down a door and "fought" or "dealt with" 5 goblins or 5 guards? The generic "bad guy" is just a placeholder meatbag who is irredeamably "evil" for us to fight, conquor, and rob. We arbitrarily label them as "Evil". We do not "murder" goblins, because they are bad and evil. We "deal with" them instead. Notice the wording?
I'm not trying to judge you or any one player, I play dnd too. I'm just aware that in dnd we solve all our disagreements by murdering people, and that the people we kill are not "people", they are "evil" or "monsters". Even though they are intelligent and obviously have culture and families and lives too.