Or taking a different view that concurs with yours: investing in index funds or broad ETFs lets me match or beat most long-term investors with nearly zero effort. There's no need for me to waste my time reading "financial news" or developing super fancy HFT algorithms like some posters here have done. I just need to buy those index funds at my desired asset allocation and I'm good to go. Repeat until retirement. Very simple.
Granted, I do complicate things a little by insisting that I never sell anything I buy, not even for rebalancing, until retirement (otherwise I wouldn't be buying and holding in my eyes). However, I get around that by constantly rebalancing with new money [1].
Honestly, I find it rather jarring that as someone who usually frequents /r/personalfinance and Bogleheads, I see lots of investing suggestions on HN that do not involve indexing.
[1]: http://optimalrebalancing.tk/