Well, Alex, of course you have plenty of RCTs and meta-analyses that prove a high carb diet is efficacious?
Incidentally, most of the published RCTs on various diabetes treatments consist of only a few dozen to a few hundred subjects and a couple of clinicians. Meta-analysis are tricky to conduct properly too. So, I'm not sure small-scale RCTs and meta-analyses will answer the question. I suspect that those that produced this literature will not have the scientific capacity to consider the finer points of RCTs and meta-analyses anyway.
In my opinion, if people find in their experience that low carbing works. Then, that is evidence it works. Clinicians will do well not to ignore patient experience. You too - who, judging by your posting history, are clearly against low carbing - will do well to be less antagonist with your posts and just accept that for some people, it does work. If low carbing is the only way some people can control their diabetes, then good for them, because at least they are controlling it.