Umm... did you even read the thread? If not, look upthread and you'll find this.
Superman outright pulls a chunk of kryptonite out of Batman's utility belt and crushes it.
Point is, it's pretty clear you don't have a clue how kryptonite works. It doesn't instantly kill/cripple Superman the moment it touches him. It takes time to work on him. Superman can certainly act fast enough to completely crush Batman before he even starts to feel the effects of the kryptonite.
Secondly, your scenario is, to put it bluntly, idiotic. You just presume that Batman will fling a kryptonite batarang at Superman, hit him on the head, and knock him out. That's beyond stupid. As I said, it takes time for kryptonite to work on Superman. So bopping him over the head with a kryptonite batarang won't do much. It certainly isn't an automatic "I WIN!" button for Batman.
And even if just having it graze his forehead was instantly deadly, there're a million things that Superman could do to avoid getting hit by it. He's faster than the speed of light. You don't think he can dodge out of the way before it hits him? He flies, so he can easily stay out of Batman's throwing arm range. He could shoot the batarang out of the air with his heat vision. He could blow the batarang back at Batman with his super-breath. He could rip a chunk of rock out of the ground and block it. Either way, if Superman doesn't want to get hit by Batman's batarangs, he could easily avoid it.
Moreover, he's superfast. In the time it takes Batman to even
think about using a kryptonite batarang at Superman, much less grabbing it, Superman could move at light speed and beat Batman senseless. He could burn him to ash with his heat vision. He could freeze him with his super-breath. He could punch the ground so hard that the quake will knock Batman flat, and maybe even create a fissure in the earth that'll swallow Batman. He could fly up into space, grab an asteroid or a satellite, and chuck it at Batman from orbit.
Either way, there's no way at all that your scenario would ever result in a Batman win. Even a brain damaged Superman with the mental capacities of a two-year-old could still easily beat Batman under that set of circumstances. Hell, that Superman would be even more dangerous, as he'd have less control, and would probably just kill Batman, as opposed to knocking him cold.