Okay, I didn't know that. I will remember it next time I have to deal with such people. Good to know.
What I think is obviously missing? Simple, Y Combinator's main page displaying a huge banner that says "we don't care about anything non-software, go away." It would have warned me right from the start. They never explicitly say it, they just heavily hint at it (e.g. they ask for your github ID, which you don't need unless you do some sort of coding) and I'm here to say quit hinting and just admit it out loud. But I believe that's also typical - what we hint at, it's actually an axiom. What we recommend, it's actually required. I believe that's not right. Simple as that. No hard feelings.