do you still have to play 2 mana to attack the planeswalker?
No, when attacking it isn't redirected damage like when using a burn spell, you attack the Planeswalker directly.
{Propaganda} indeed. Check out the wording of {Circle of Flame} for reference.
Ah {propaganda}...turns any magic game into an 8am Los Angeles commute. Fortunately made before planeswalkers, otherwise I'm sure it would have been on there.
Seriously though, that card makes me poop blood.