I think the people that read HN is a different demographic from those that submit, and again different from those that comment. If you look at people's profiles you can quite starkly see some are uploaders, some don't upload or comment, some only comment. Having said that, HN is more obnoxious nowadays to me than earlier.
Suprisingly, Reddit is cool if you choose your subreddits wisely. But apart from that, tbh I think it's probably better to read actual books on topics you find stimulating or maybe something like the Economist.
