I don't think any game jam should be set up as a popularity contest to begin with! I don't blame you at all and I don't think you cheated in any way, it was just a strange set up and a bit confusing for everyone. What you did was not against any rules. Luckily they have said that those voted scores won't be a factor in their final decisions, so anyone accusing you of "cheating" is just being silly at this point. If you are new to game dev, just keep in mind that there are a lot of overly competitive people that get really negative during game jams, just ignore them and keep doing what you love.