Even if the deal flow was exactly the same, just having the founders suffering less from information assymetry would be a stone in the shoe of the Angels.
Think of it this way : if YC did all the same things, but also turned founders into being Angel patsies at dealtime, do you think they would be upset about it? I would guess it's the information about how to negotiate, and what a good deal looks like is the problem. I'm sure they love the concept of demo-day to go deal shopping, but would prefer it if the products didn't talk back.
Yes, I believe so.
How can it be a "PG vs Angels" situation when the parties involved are likely some of YC's portfolio companies biggest "supporters"?
That question might be better put to those Angels in the bar...