what? It doesn't, if for what ever reason you can't set up your saddle without it sloping up or down then yeah it's not the right post for you but that still has nothing to do with saddle drop?
Are you suggesting that you'd move your saddle higher if you can only set it up sloping down?
It has everything to do with your saddle sloping forward if your setup is fucked.
Or your Seatpost won’t let you set it any other-fucking-way!