Why? So that we can tell Christ, "You did not choose us be we chose You?" That is, after all, what you are saying. But that is not how it works. Man is either a slave to sin or a slave to righteousness; it is an either/or type of deal. Only our Lord can make us a slave to righteousness.
If you want to talk philosophy, do not do it on a religion thread, and frankly, I have more important stuff to think about that calvinist fantasies.
If you want to discuss Christian beliefs, a scripture reference would be a good start. Where did Christ teach that we are His slaves?
I think I explained why in the post, HD. If we have no will of our own then someone is making our choices for us.
Is someone making your choices, HD? And if so, how would you know?