Other people have answered in specific examples, but for me the problem is just it isn't a good website for discussion.
Populist answers that get in early and are digestable get upvoted heavily. Long, wordy answers that don't give an easy answer are not voted up as heavily as they take longer for people to read, or worse yet, sometimes they state their point early, provide their argument later and people dont read the justification and just upvote the top part as it aligns with their point of view.
Reactionary posts get a lot of traction because people get caught up in emotion and upvote. A placid answer saying "guys lets calm this down and wait" will not garner many upvotes because its not particularly polarising. Nuanced answers tend not to be as popular as ones that give a clear bad/good guy answer.
Worse than that, almost nobody reads the articles linked, its mostly people reading a headline, going to the comments and finding the first comment that falls into their world view. Too often you find an article that is quite good, with a highly upvoted comment rebutting the article in a way that makes no sense - because people aren't reading the article, they are just assuming and then finding the comment they -believe- counters the article.
I browse reddit constantly, but I don't think it represents issues well at all, it basically is a bandwagon simulator.
r/LateStageCapitalism is on the front page all the time. Its rules include "Support for capitalism--and the political parties which uphold it--is strictly prohibited". Counterbalanced views are not front paged on a regular basis.
Reddit made sure idiotic pro-Trump subreddits were left off the front page. It didn't do the same for idiotic anti-Trump subreddits.
r/TwoXChromosomes, also regularly appearing on the front page, is about as liberal and pro-choice as you can get.
I don't like Trump at all. All the things going down right now were easy to see coming. But he got well over 40% of the popular vote in the election and still has millions and millions of supporters. Absence of pro-Trump viewpoints on the reddit front page is conspicuous, in my opinion. Likewise any number of other relatively popular viewpoints.
I was banned from latestagecapitalism when I argued with a user that was recommending murdering business owners was a necessity to improve the world.
That sub used to just be a cynical but funny place to comment on the general degradation of morality, then it swung to extremism like seemingly every Reddit sub.
And public violence is a common sentiment over there, too. Not even in a joking way. If prompted, they will inform you that peaceful methods will never work and fighting in the streets is necessary to seize the means.
Just look at it... 30% of all posts are dog/cat related. 10% are top news sources that I could get from news.google.com beforehand and the remaining is just a void of randomized "cool" posts that many will forget within hours. Nevertheless, I still go on it everyday and am pleasantly entertained.