I'd say apathy. Because if you are apathetic you aren't going to do anything about anything, but if you are ignorant you don't know that you're not doing anything about anything.
I think ignorance is worse, because that can lead to harmful actions (like those motivated by ignorance to the humanity of others), and apathy just means one does not care, not that they won't act.
In simpler terms:
Ignorance = I don't know
Apathy = I don't care.
But you are right about apathy, I think it's much worse.