Samsa - I took a while thinking about the second part of your post, and I'm still thinking ... but:
I think what you're asking is whether parents are not listening to/taking account of their dc wishes and also "living through them/over-identifying with them", in that they're pushing their dc for their own self-aggrandisement; a reflected glory in their dc's achievements? Would I be right?
Personally, I think you're wrong but, well, if they do, 11+ parents don't have the monopoly on that! I see it all the time at primary school, irrespective of the dc's destination at secondary transfer!
I think what you're reading is something different. As I said before, a lot of it, is, I think, down to stress.
Secondary transfer is weird. It's one of those significant stations on the pilgrimage to adulthood for a child. It's a point when, almost ritually, you as a parent are forced to let go a little bit more.
I think that is where some of the stress comes from. Parents post here the thoughts that don't get expressed in RL, and certainly not to the dc! They are, I think, amplified by this RL inexpression. I sometimes think it's like a confessional!
Fwiw - I don't think the stress is, in fact, all about schools. I think it's existential. And it's unmapped because too many existential philosophers aren't parents - or don't think as parents.
It's the stress of easing your hand, slowly, from that of your dc. But, you know, let go we all do. Allow them increasing autonomy, we all do. Witness and enable their freedom, we all do. Whilst all the time carrying within us the absolute knowledge of their vulnerablity, their irreplaceablity,the knowledge of the absolute devastation that we would experience should we, somehow, fail to protect them. And all the time knowing that the urge to protect and cosset has to be held in check - their freedom is a gift we must give.
So, in RL, we bend down, and try and see the world as they see it, while keeping in our mind's eye the horizon we see as adults. We try and balance the choices they make, with the experience and years of a (wise) child, with those we would make, for them, with our, different, experience, and the longer time of an adult. Hopefully, we get the balance about right.
In our heads, though, ... well, something quite different may be going on! That suppressed urge to do it all for them, to take any of the risk that necessarily attends the gaining of wisdom and experience, protect them from any future pain - well, it has a loud, insistent voice!. But, hopefully, it's an internal monologue. And maybe some of it gets voiced here. And maybe it doesn't.
And, of course, I'm talking about far more than schools here! But, weirdly, secondary transfer brings all that, far deeper, stuff to the surface; partly because of its strange ritual quality! How mad!!
Anyway, I just don't think all the parents on here are driven lunatics, sacrificing their children's happiness for the sake of reflected glory.
But then, I am a sunnymummy!