The scale they have, so I think that's a fair line of argument. And they do discuss some of these factors, e.g. people with pre-existing illnesses were in many places prioritized. On the other hand, policy of prioritization vs it actually happening is an issue, and can be mixed with other things again - e.g. my impression is that in many places people in care homes had it a lot easier to get vaccinated than similarly ill people cared for at home.

But I think the "systematic mis-categorization" is more "not the correct categorization for what we want to do with the data", unless I missed something?

Data collection around all this is something where most countries seem to not be doing a great job, which is frustrating when looking at data. (On the other hand not too surprising, many health care systems are intentionally designed to not track everything centrally, people fall through gaps, ...)