If a surgical operation can be avoided, and is not needed for medical or mental health grounds, why should a natural process (vaginal birth) be avoided?
There are a number of problems with the way you're framing this. First of all, you're assuming that the natural process should be the default. But as you have admitted yourself, you don't think natural processes are generally better per se, so really you would need to provide an explanation as to why you're doing this with birth. Privileging the natural simply because it is natural is illogical, and given that nobody does it in relation to everything, it's inconsistent.
The reality here is that there are two possibilities with their own risks. VB has more risk of tearing, incontinence and dystocia. CS has more risk of future miscarriage, stillbirth and pregnancy complication. It is simply a question of balancing the risks for each woman: that is the only appropriate way to frame this. If you're talking about need, you're doing it wrong. I mean really, who are you to say a woman doesn't need to reduce her risk of prolapse, for example? Or to eliminate the possibility of shoulder dystocia? Why is someone's anxiety more important than someone else's continence? It's at best an absurd construct.
Are you saying that there should simply be free choice, absolutely regardless of reasons? For example, would choosing c-section because it is possible to state which day baby will arrive on, unlike the uncertainty of vaginal birth, be an acceptable reason, because simply any reason is acceptable?
Certainly. All pregnant women with capacity should be given the choice. It's interesting that you mention choosing the day here as a reason in that you seem to be presenting this as perhaps a less 'good' reason? Unless I have misunderstood. But actually, a woman might have existing children who need childcare, she might only be able to rely on family support at a particular time. So choosing the day is a fantastic reason! Could reduce her risk of PND, since we know this is more likely when there is no support.
And I think this can only be answered by also considering if this also applies to all other medical procedures too - are people entitled to absolutely free choice of procedure, regardless of cost or reason?
You're allowed to think that, but given that it's not at all analogous to this issue I consider it to be an unhelpful distraction. I posted what I thought was the appropriate comparison a couple of posts ago, and in that scenario yes the broken leg man should certainly have the right to choose.
And following the logic, do you think that at their booking in appt. women should there and then be offered the choice of vaginal or c-section? Is the fact that this doesn't happen, denying them their fundamental rights to choice?
No, later than booking in would be better. Yes.