If people can’t be bothered to log an issue or thumbs-up/comment on an existing one, it can’t be such an important thing to them.
I'd never write a github issue unless I have a clear use case for a feature, or a clear reproducable bug. And on the receiving side, I hate unclear discussion style issues - "This is cool but its slow when I do (hacky unsupported thing)".
But with comments you surface much more "raw" reactions to things. "Oh cool - I didn't think about the problem like that". "I've always wanted something like this for (some weird problem)", or "How come everyone who tries to solve this problem uses approach X? Is there a reason people don't use approach Z?".
Maybe as a maintainer, the beauty of HN comments is that you don't actually need to reply to them. Github issues sort of demand a response by their very being. If you leave them, they get in the way and make the issue repository basically useless. If you close them without responding, its kinda rude. And responding takes time. Comments, on the other hand, can just be comments. Its lovely.
It's generally pretty easy to look at the tone of how recent issues are handled and know if the maintainer is drowning and would prefer that you keep the noise down, versus whether they're likely to feel energized by interacting with enthusiastic users.
You don't have to be hardcore to leave helpful feedback. If you think it's the latter, go file an issue.
Whats your point? Aren't people allowed to discuss stuff other people share with them on the internet?
I think their point might be: such discussion might be fun for users, but could be unpleasant or unproductive for the maintainer. That's a totally different concern to express from "don't talk about this at all." Personally, the first thing I do with new software is see what I can do with it, and what I might want to do with it, and I can get carried away in a discussion thread. There's no harm in remembering that the maintainer might be here reading, and keeping their reaction in mind is no huge ask.
If I'm feeling overwhelmed, if I'm feeling burnt out, if the comments are too much or are unhelpful or are rude... I can tune them out. As the author, my goal was to solve a problem I had. I solved it. If the solution benefits someone else, that's gravy, but I've already put my energy back into the universe by sharing my solution one time in the first place.
Maintenance is a choice. Share and enjoy.