Our entire popular culture from 1941 until at least the 1980s was about pushing simple good vs. evil narratives. At some point, though, people started to ask harder questions based on human nature. Why would millions of people fight for a nation that we decided was "evil"? The more they found out, the less certain the simplistic picture became. As people tried to understand what motivated, for example, Confederate soldiers to fight to "keep the slaves in chains", they then moved on to their favorite scifi and fantasy series to try to figure out what would, say, motivate Imperial stormtroopers to fight for the Emperor.

The answers create good debates for philosophical discussions. If the Rebel Alliance is about "freedom", but that "freedom" then allows the Hutts to expand a galactic criminal enterprise involving drugs, human smuggling, etc., is it better than an Empire that seemed disinterested in oppressing people that weren't openly in revolt? Was developing the Death Star really evil if someone else would develop it sooner or later?

There is a certain degree of contrarianism, but again, I think it's because black and white stories have been shoved down peoples' throats for so long they're sick of it.