Why? Because I like playing the lottery with stocks. On average, I might do slightly worse than the market but I retain the potential for massive, life-changing upside. And that's really all that matters to me.
If I put $100,000 into index funds I might reasonably expect that to be worth $108,000 next year. That would literally not change my lifestyle at all, as it's approximately equivalent to accepting 1 or 2 extra short contracting gigs.
If I put $100,000 into stocks I personally pick, I might unreasonably expect it to be worth $1,000,000 next year. That would definitely change my lifestyle. I can also reasonably expect it to be worth $0, which I'm fine with considering I'm young and gainfully employed.
I just don't see the problem with buying stocks as lottery tickets whose expected value is 1.03% (sub-market) but whose potential value is 1000%.