I think what's most frustrating about Reifags is that Anno made Rei to represent what every socially inept anime watcher would want, just some quiet, submissive girl of nothingness with no real features. Rei isn't even a person, she is something else. An alien being, to give a different perspective on humanity.
So then when people say "omg I want to make Rei my waifu!!!" not only are they absolutely not getting what Anno's point is, but they're exactly what he's trying to "Criticize". She's really not human, at all, either genetically or mentally. She's this weird amalgamation of a blank slate that ends up caring for only the protagonist. In other words, a fake person. It's absolutely not anything that happens in a real human life. The whole big theme of Evangelion is actually facing life as it is. Because it's hard and it sucks but you can't run away.
Asuka represents this theme the best for Shinji. She's harsh, has flaws, can be difficult, but she's a real person while Rei represents an idealization of a woman. Just as Instrumentality is accepting this "fake dream world" where everyone stands around you and tells you how proud they are of you and everything is great, rejecting it leaves Shinji in this desolate wasteland, but you have to reject it. It's the only way to actually face life and move forward. You have to pick Asuka. Rebuild also follows this, as by picking Rei, Shinji does not move or evolve, attempting to run back where it's safe (back to mother, basically) rather than facing the consequences of his action.
I sympathize with Anno. As an artist, it must be annoying that despite having her drawn to be weird and unlikable, people misinterpret her and she becomes one of the most popular characters ever. Speaks volumes about how awful people (fans) are.