Think about how it would work in practice. It's not going to always be a cool professional interaction: "Hey, I was wondering, could you give $50 to my crowdfund?" You: "Nah, sorry." Them: "Okay, thanks for your time."
It'll be more like "Contribute $50 to my crowdfund. Pleeaasseee I need this job. I'm having a tough time, I won't be able to make my rent if I don't get this job, and my wife's about to have our second child. Come on, man." It's really hard to refuse, but you'll also be resentful. You don't go around hitting up your former coworkers for money.
It turns a social relationship into an extractive one. Which gives people the heebie-jeebies. You're basically being told "Give me money, or I'll kill our friendship." It's approximately as appealing as someone who says "Give me money, or I'll kill your dog."
I certainly understand having a seething hatred for a company that makes money by encouraging my friends to act that way toward me.
Also, a lot of SWE's are introverts. I'd like to think I'm pretty good at what I do, but I don't know that I have contact information for 20 former coworkers, let alone be able to put together 20 people who know me well enough that I think they'd put $50 on me.
As to YC would have funded this: For founders and VC's, the line between social and business might be pretty blurry. It might be a cultural blind spot, if you're deep in the VC world, you're probably an extrovert with hundreds of business contacts, and you've maybe forgotten how taboo it is to pitch your acquaintances for money as a normal person.
It seems the Internet quickly gave the company a taste of the public's reaction when they started showing off their "brilliant" idea. And to their credit, they went offline more or less immediately.