They made choices for reasons. Borders aren't a universal truth, countries disagree on these matters and the WHO has to work with that because they are a global entity.
It is obvious why it happened, but it is nevertheless perfectly reasonable. If anything the Europeans are the problem; resisting being aggregated into sensible units. But nobody begrudges them that.
> They should be listed separately as in the fight against the virus they act as independent entities using their own resources and local policies.
Don't the Scots have their own health system? Maybe Scotland should be listed separately from England?
The situation reports list Occupied Palestinian territory separately; they probably aren't going it alone. Maybe the WHO should have merged them?
There is no end to the nitpicking that is possible. There isn't anything particularly important in the aggregations they are using.