That is right... and it is possibly the root of your problem.
I'm sorry to say — and I expected that to begin with —
but the kind of "date-drilldown" you wish to achieve
is really not what the toc is designed for.
In the end, why would you want or have all these month and years tiddlers?
It appears you possibly have no use for them, except maybe as:
Also, would a generic January need to have
each year as a tag where if there are tiddlers for it?
Anyhow, for a date-drilldown, we will need
a new, dedicated macro or rather widget, I presume.