It would have been a clean hit if the receiver had caught the ball. But he did not.
Saying it is not a clean hit is not the same as saying it IS a dirty hit.
If it had been a clean hit there would not have been a “missed penalty”.
It was a clean hit. It was a tenth or two of a second before the ball got there. That makes it a penalty (if they call it) The receiver catching the ball has nothing to do with it either way.