Sometimes those people aren't realizing that they're making things worse, they're just in a depressive spiral and can't see the other end, or see how much good is still being generated while other things are temporarily worse, or see that different tradeoffs have been made to make things worse in some ways and better in others. Just as people can delude themselves that they're always making a positive impact, people can delude themselves that they're making a negative one. The latter tends to be more costly, though, which can sure be annoying to those with a bias for a more cynical or pessimistic outlook...
Trying to ascribe positive/negative impact to strangers isn't usually a useful exercise, even if you have enough data to make a solid case. It can be cathartic -- imagine a different world where programmers making things worse would screw off and go do something else that's not programing! (I have a similar imagining, like of a world where programming is done by those who love it even outside of work -- even though I've worked with and helped hire excellent engineers who only treated programming as a job, they weren't my favorite to work with, and some were very much not excellent.) The best you can hope for is to trigger some self-reflection, and I do think that's important on an individual level. It's better to not make the world uglier, if you notice yourself doing so, and it's not just a distortion of your thinking, then you should probably stop, do something else, or figure out if it's at a level that you can compensate. A Richard Stallman quote I like:
"The straightforward and easy path was to join the proprietary software world, signing nondisclosure agreements and promising not to help my fellow hacker....I could have made money this way, and perhaps had fun programming (if I closed my eyes to how I was treating other people). But I knew that when my career was over, I would look back on years of building walls to divide people, and feel I had made the world ugly."