Insurrection seems to be the only Trek film that sparked endless discussions about politics and morality. And people still criticize it for being bad. I'd say it's the most effective, literally thought provoking
What you can also clearly see is how films don't change one's opinion. Quite to the contrary, your perception of the entire film is shaped by your predefined opinion. Some think the Ba'ku are the actual egoistic bad guys and deserve everything that happens to them, others think that the Ba'ku are innocent and absolutely right in what they do and how they do it, all in accordance to how they see the real world anyway. But nobody walked out of this film saying "Gee, I never thought of it this way, this film changed my mind."