I'm afraid I have to disagree with everyone. Pretending to agree with the coach and then doing what you want is deceitful. It is a ticket to oblivion if the coach figures it out. More important, it is disrespectful, at best, and a flat out lie, at worst. There is no argument here about the incorrectness of the hitting instruction, but that is a secondary issue.
I think the way to handle it is to be honest and simply tell the coach that you're having a hard time buying into this style of hitting and why. And that you are willing to try anything, but would like to be sold on this method of hitting. I know at this point it could go one of two ways, but if the coach has an open mind at all, then he/she will respond favorably. If the coach doesn't have an open mind and it's just his/her way or the highway, then you're stuck and have to make a decision. Stay and deal with it or leave the team.