These aren’t serious people.

I didn’t look at it this way at all, but you’re absolutely right.

I do find it strange I only found one mention of Taliban here: https://www.state.gov/foreign-terrorist-organizations/

Designated in 2010. Probably because exactly what you said. The historical mess.

Aren’t they recognized as a terrorist group vs a government? I’m guessing legitimacy is the main issue here.