Re: But WHY is nagging acceptable?
My opinion: some of it might just be you. Some of the examples you gave, I can see how they are...well, not nagging, necessarily, but definitely not a good way to behave. Others, I think it might just be the way you took it but it wasn't intended as nagging. Asking you to come meet their parents, to me, is not nagging but is an attempt to move the relationship forward. Asking why you don't surprise them at the library...if asked once, I think it's a legit question, asked more than once could be nagging.
I also think that if you're noticing this same thing with ALL the women you've dated, it's time to consider that the problem is either you taking things wrong or looking at why you continue to choose women who nag.
Plus, I notice more than once that you say you "know" it will lead to/end in nagging. You will always find what you expect...even if it doesn't really exist. If you're determined that a woman will nag you, then her simply saying "hello" to you will be nagging.
I get that you're frustrated after having so many dates/relationships go sour. But I would get back out there, try to be more optimistic and see what happens.