Did you know that minimum wage is compensation for your time only? For simply showing up for the duration of your shift and being ready to work. You are not obligated to lift a finger. For any productive contribution during that time, you are owed extra. If you make minimum wage you are working for free. 100% of your labour is being stolen. If minimum wage is $15 and you're making $18, you're being paid $3/hr for your work.
This is why they resist raising the minimum wage. They don't respect you or your time. We must reframe our argument from raising the wage to demanding we receive compensation for our productivity.