The INTP villain is someone who adopts utilitarianism and decides rather autistically that to maximise aggregate net present value of utility, we must do something that neurotypicals would consider to be immoral.

We will throw the fat guy off the bridge to stop the train and save the 3 people stuck to the tracks.

If an INTP got into a dictator position (and it was forced on him because they don't want to be a dictator), some things that wouldn't surprise me:

• execution of all violent prisoners because the net present value of their cost can be reallocated to save 15 starving people per prisoner. She reasons that the emotional impact in the general population is outweighed by the increased disincentive to commit violent crimes. Thus their execution and reallocation maximises overall utility.
• bulldozing heritage homes because it's more efficient for apartments to be there.
• letting in a crapload of immigrants because he has not an ounce of tribal identity, the only objective is aggregate net overall utility on NPV basis.

we can be imaginative here.