I wasn't too sure about this until I checked today and saw a breakdown of my votes cast on my profile.
The Electorate badge states: Voted on 600 questions and 25% or more of total votes are on questions
I've voted 639 times, 634 up votes, 5 down votes with 354 votes on questions and 285 votes on answers. I believe this is what the badge is asking for, unless I'm mistaken.
Is this a bug?