It mattered a lot to the people in the subreddit who were upset enough about that and other things to create their own website and move their community off redd

It mattered a lot to the people in the subreddit who were upset enough about that and other things to create their own website and move their community off reddit. I think it's less about the technical aspect and more about the expectation that people with the ability to change your comments won't do that. If you wrote an opinion letter to a magazine, and they published it, but only after changing a few words in your letter to make you seem dumb, everyone would understand why you were upset even though nobody would doubt that magazines have the technical capability to do this.