In Islam a muslims would always choose to regulate their lives according to Gods guidance as laid out in the Quran and Sunnah -Shariah
So given the chance to choose Sharia, or ‘man made laws’ it would be shirk to choose man made laws (putting aside urf (customary laws)
However there is no such choice living in a ‘Democratic’ Country
Rules (laws) are imposed, through the threat of incarceration or theft of your property.
So given that the laws are imposed, you are no longer in a position to choose how to regulate your life. much of it is imposed.
Given this situation. A vote is not a vote for ‘man made laws’. it is a vote to have the least crappy rules imposed on you.