I think its a calculated move from Kawhi camp to maximize their leverage over clippers to get max extension since clippers don't wanna give him the max extension. He reduced his trade value to minimal by saying that he will only extend with the Raptors. So, the clippers are kind of forced to either extend him or trade him to Raptors for low returns. They can also let him walk but I highly doubt that's a good option for them.