Sorry, I started writing this this morning and then haven't got back to it until now, so some of this might be irrelevant/thread may have moved on but I wanted to finish it anyway.
YY to not everything is PDA - according to MN so much is which was making me feel a bit frustrated, but recently listened to a couple of podcasts (SENDCast) with Clare Truman as a guest and she explained PDA really really well and I do think a lot of what gets touted as PDA online isn't really PDA - it could be demand avoidance, which everyone experiences to some extent, but demand avoidance by itself is not necessarily PDA. I think sometimes people do use "demand avoidance" and PDA interchangeably online, which doesn't help.
I think the logical consequences argument is interesting because I can absolutely see - it sort of "feels" intuitively right, and I used to be quite a fan of this idea, but lately I've come around to thinking that actually, the point of a logical consequence is not usually repair or education, it's supposed to be at least mildly aversive, similar to time out/loss of privilege etc. (e.g. logical consequence of not coming off game console at pre-agreed time = lose access to console for the next day). So the point of it is still to be something DC wish to avoid, and essentially they are going to experience it the same, and it's going to have the same effect, as a generic punishment. Yes, it might be that DC are slightly more agreeable to it because they see it as fairer than e.g. not coming off console = loss of pocket money/extra chore, but that's about it in terms of benefits. (And you can achieve this in other ways anyway).
Logical consequences also have one really big flaw which is that in theory you are supposed to tailor them to each individual incident, which means, a lot of the time, making up a consequence on the fly. This can be a problem because in the heat of the moment, most people go too harsh, or too long. In order to be effective, you actually want consequences to be fairly minor because the effectiveness of them doesn't increase with how harsh they are, (except that if the child is genuinely afraid then you will tend to get immediate compliance in that moment - this however has no ongoing effect to change behaviour, and has a lot of negative effects, so not recommended.)
And if you take it out of the moment and say OK, you're getting a consequence but I need to decide what it is, that's not ideal either, because you're taking the consequence away from the moment which hugely loosens the link that it has to reinforce that behaviour. It can also be scary for a child because they don't know if you're going to impose something very harsh or not. And I think it's confusing for parents - there is a thread every week asking "What's the logical consequence for X?"
So there is an argument for saying actually, it makes a lot more sense to have a generic, decided-in-advance minor and token punishment which can be used if you're going to use consequences, because it allows a parent who might be under quite some strain against a child who is really pushing their buttons to calmly and rationally respond with something that isn't going to be totally OTT and therefore be interpreted as raising the stakes/further conflict.