Because it's just another transformation with a hair color change and power boost. At this point it operates no different than anything else. Goku dodges just like he would if he was stronger and faster than his opponent in any other form. It's just a new look with supposed differences to how it works. It should theoretically make him unable to be hit and able to strike precisely where it would cause the most damage. So Goku would be a precognitive ninja with chi-blocking attacks. But nope, he's just stronger and faster than before.