Being an exception of the Aufbau principle, Thorium has an electronic configuration of $\ce{[Rn]}\mathrm{7s^25f^06d^2}$ instead of the expected $\ce{[Rn]}\mathrm{7s^2 5f^2 6d^0}$.
Two other elements, Lanthanum and Actinium, also showed such an anomaly as $\mathrm{6s^2 4f^0 5d^1}$ and $\mathrm{7s^2 5f^0 6d^1}$, respectively. But we placed them both in the d-block of the periodic table.
Since, even in Thorium, the last electrons occupied d-orbitals only (disobeying Aufbau), then why is it placed in the f-block of the periodic table. I mean, it should be placed in the d-block, shouldn't it?
Edit: Note that here, I don't intend to ask or know how or why the 2 electrons disobeyed the Aufbau, and occupied the higher energy 5d instead of lower energy 4f.
Rather, I want to know only that why it is kept in the f-block when the last orbitals which the electrons occupied were of d-subshell.