I don't know of any VC's or Angels which won't except a business plan. I think they are more open than ever to finding new companies. I've never had a VC or Angel refuse to receive a business plan. I have contacted three on the phone and they all gave me their email addresses to send pitches/packages to. Have you actually sent VC's and Angels business plans and they've sent them back unopened or are you just assuming they would? Have you ever emailed VC or Angels and they replied to the email saying they will not read the email or are you just assuming that would be the case?
What you are calling an "public open application process" to me is simply freedom of speech. You can send a letter or email to anyone in this country, including VC's. By open, I would think the list of companies which apply to Y Combinator would be made public. As far as I know, and I may be wrong, that list is not made public. That signals something to me. It may not to you.
If you accept Y Combinator reason for providing absolutely not one single word of feedback as reasonable, that is fine. However, I think most people would agree that organizations which truly want to help, would provide some, even if minimal feedback pursuant to an application. Off the top of my head, Y Combinator is the only organization I can think of in my life which provided absolutely no feedback pursuant to an application. That also signals something to me.