Suppose you want a minimum wage law of say, $20 per hour.
You need to ask yourself, does a $20 minimum wage law mean every worker is worth at least $20 per hour? If no, then the law is creating artificial unemployment. If a person is only worth $15 per hour, it is now illegal to hire them, so they remain unemployed or they must work off the books. The point is, the law doesn't benefit anyone. If you are worth at least $20 per hour, then the law doesn't effect you at all. If you are not worth at least $20 per hour, then the law prohibits you from being hired, which makes you, and by extension society, worse off.
Remember, a minimum wage law does not and cannot change the value of anyone's labor.