Films are not solely intended for you to evaluate morals of the characters
Many people enjoy discussing and judging the morals of characters in films, but that's not the main point. Very few characters are entirely good or entirely evil, which tends to result in dull and poorly made movies. Regardless of whether viewers resonate with the story, they should show compassion for the characters. It's important to interpret their motives and circumstances to understand what led them to make certain decisions and to reflect on ourselves.
Because it makes them more interesting. If I kick puppies just because I'm "evil" and I like to kick puppies, thats a boring one dimensional character.
If I kick puppies because I genuinely believe that will cure cancer, then that's more interesting.
They don't need to have extremes or even contradictions, just some kind of nuance other than good/bad. Spiderman's moral code being based on not stopping the guy who then killed Uncle Ben in the early 2000s films is nuanced. Captain America standing up for doing the right thing based on his personal experience is nuanced.
It doesn't have to be moral nuance though. But that is one that gets a lot of criticism because it stands out so much for heroes and villains.
I feel like that is more of a reflection on how audiences can critique a film beyond which parts were good and bad.
Critique of cinematography requires an understanding of visual arts. Critique of sound design and scoring requires an education in music. In contrast, methods to critique characters and plot are taught in every high school literature class.
This (supposedly unpopular) opinion could have used a couple of concrete examples.
I would go further still: it is generally a bad idea in life to evaluate people's morals. Make clear what your own are, try to live up them, and leave it at that.
But that is another "unpopular" opinion altogether.