Correction to description:

The galleries tab is the main_personal_galleries_list block. It should show all personal galleries and their subgalleries recursively.

Still, I'll leave the request for configurability here open.

So it should show all a member's galleries, and subgalleries under those. I think that's a reasonable behaviour, and that configuration would be over-complex (at a certain point, one has to make some assumptions, to avoid getting entangled in too many possibilities and settings and complex code - and leave codifying exceptions to addons). If it's not happening as I think it is, please open as a bug.