Plenty of active funds also give you roughly market returns, and it's not very difficult to do the same if you're investing for yourself. The important differentiator for index funds is that they have extremely low fees and take up none of your time.

That's simply not true. The core tenet is to buy mechanically according to some rule. Many indexes are not "the whole market".

They appear to know more than you, too. They know not to change rules that have protected their investments for a chance to get into a risky bet on the ground floor.

The S&P 500 has had these requirements for decades and the approach has worked. This is really a statement that they aren’t going to change what worked so that a few billionaires can manipulate it.