"My country lost, so the bad guys won"

Yeah, that's generally how history goes. "Bad" is ultimately a pretty subjective term, and what qualities make someone the "bad guy" have changed quite a bit throughout history. More often than not, violence and atrocities are committed by both sides in a conflict, but the losing side has theirs written down while the winning side gets to forget or justify their own.

Example off the top of my head would (of course) come from WW2. Genocide is pretty much at the top of the list as far as reprehensible acts, but you better believe that if the Germans had won then it would likely be something that was either forgotten or simply seen as an ugly thing that had to be done, much like the allied bombings (including atomic bombings) of countless civilians during the war.

The mongols completely obliterated entire populations of select cities and capitalized from the face of the earth, so they're often seen as another one of the ultimate "bad guys" in history, but of course from their own perspective that's not true at all. The Mongol conquests are still being looked at in an ever-changing light, with factors like increased trade and safety being acknowledged more and more.

Another one would be the Ottoman conquest on Constantinople. That was definitely seen as a "bad guys won" moment in Europe, but of course in the middle east / Turkey it was a heroic moment in which a city that had spent a long time decaying finally had the chance to be rebuilt into the shining capitol they believed it deserved to be. People often forget that while many European nations had dreams of rebuilding the lost Roman Empire, many Muslim nations were actually trying to do the same.

I may have rambled in my answer more than I meant to, but I guess the overall point is that there isn't really a definitive "good" and "bad" in history, and which is which is almost entirely a matter of perspective.