For one thing, because of the high rate of false positives. I remember watching a paramecium on a microscope slide, and being shocked at how much it looked like a dog searching for a bone (or a skeptic trying to out a woo, or Robert Wright trying to out Daniel Dennett as a Satan worshiper
Let me throw this ball into the melee.
westprog asserted IIRC that a Turing Machine could not be conscious because it didn't have IO or timing control, and therefore couldn't perform interactive functions like controling a ball catching robot.
I'll propose that a true ball catching robot was conscious, because it saw the ball, remembered its position, saw the ball a fraction of a second later, compared its present position with its remembered position, extrapolated its position when it was near enough to catch, rehearsed catching in its internal model of the environment, then reached out its mechanical hand to the ball's future position and instructed the fingers to close in time to grasp the ball before it bounced out. I'm proposing that the robot had a tiny spark of consciousness. Real consciousness. If not, why not?