You also have to consider what the transport did. A Battleship needs 1 second to destroy a transport. If they stopped the transport, and after being CDed, he continued to cruise, the pirate knows this won't go anywhere.
I've encountered many traders, who don't give a single....ya that, and charge cruise right after being told to stop. So in this case, if titanbot stopped a transport, and he didn't listen and charged cruise, I don't see how that is breaking any rules.
But then again, that's me assuming to what happened. I know Titanbot, we flew together, and he never pirates like this, so the transport did something to make Titanbot shoot him.