While Jesus would almost certainly have considered homosexuality (and SSR in particular) a sinful abomination against God, I agree he probably wouldn't have voted in a plebiscite (or whatever it is we're having)
Jesus said 'render unto Ceaser that which is Caeser's, and unto God that which is God's'. This is generally understood as instructions to his followers to pay tax, follow roman law, and not to become involved in politics.
Keep in mind Jesus was an apolyptic cult leader. He prophecied the world would end within the lifetime of his followers. What sense trying to improve the world through political participation when the Kingdom of God was imminent?
