Steve
The key flaw in that quote from Ben that you repeat, and I must stress that most people think-it is not a 'Ben has got it wrong point', lies in: "You can choose a time parameter, but it will be different for different observers, while the causal structure is invariant "
Observation of physical existence is just that, observation. Physical existence occurs in one particular spatial configuration at a time. Observation always involves a time delay between time of existence and time of observation of that existence, because light has to travel and be received at the eye (apart from other factors which 'interfere'). So, even in a 'still frame of the film' (ie what exists at any given time), observation timings are different. When the 'film rolls' (ie when existence changes) then variance in the momentum of individual observers has an effect. But, existentially, it is just a different 'still frame of the film', the others having passed. In other words, like with like is not being compared.
"Or rather that the conceptualization of splitting the Universe into segmented unconnected pieces called "inertial frames" actually reflects what occurs in the "real world".
This is the key point. We cannot deconstruct the entirety of any given physically existent state of our reality which exists at any given time, on the basis of observation. We can however conceptualise its constituent existent states which existed at that time. The problem is that we can only effect that by association with 'its', which is a higher level of conceptualisation, ie involves several existent states over time. Think on this: what you know as the monitor in front of you, is not in the same physically existent state from time to time. It just appears that way, because we are conceptualising what physically exists in terms of superficial physical features.
Timing is a methodology which, using a conceptual reference of tick rate, enables differentiation in terms of rate of change. Therefore it is a case of 'choose a time'.
The notion of frames has nothing to do with observation, per se. It revolves around reference. To be able to effect any judgement there must be a reference, and if more than one is to be compared then the reference must be the same one (or adjusted to be so). The concern over inertial references is because it was believed that anything that was moving relatively was altering in dimension (a single force-gravity-being responsible for both effects). So, unless one factors in that supposed effect, then a moving reference is not a good one to use.
How one copes with this, if we can at that level, I do not know, but even if we consciously simplify it we must maintain the integrity of spatial and timing.
I will have a look at the reference in your post. However I note SR. Have a look at my post above in response to Ben 13/10 13.31. SR is not what everybody seems to think it is, but then you wouldn't expect me to say anything else!!
Paul
PS: hopefully I can get the rest of the paper finished, which the response above is the front end of, very soon. But I have got to prepare for a Halloween party for the grandchildren today.