One is just a straight up naive sense of fairness. If I'm going to be in the trenches with you, I had better be able to see my ownership % in a pie chart with my glasses off. If we're out here both making chairs and when we sell a chair for $100, you get $85 (assuming someone took one of the standard-ish seed rounds that are usually 10-20%?) and I get $1? No thanks.
The other sense is aware that the founder is taking various risks and blah blah blah. Ok whatever. Let's pretend somehow 1% is a fair number and just look at it from a payoff perspective. 1% of stripe? Yeah I'll take that. 1% of the other 1000 startups who had mediocre exits or just muddle along to finally do some kind of tender? I'm barely breaking even. 1% of the other 10000 startups that just folded? At least I can mop the sweat off my brow with the paper I signed.
It seems like the only reasonable way to look at this is you either join a company for a competitive wage and get WLB, or you join a rocket ship in the hopes of becoming genuinely wealthy while pouring your blood, sweat and tears into it. So taking 1% and a shitty salary and having terrible WLB sounds like a huge suckers game.