Yeah Hitler was too nice in a few ways. But, I do think he was trying to thread the needle politically. I don't think he realized the propoganda machine even back then had already been working overtime to make him and the Germans appear like murderous barbarians that needed to be exterminated.
Friendly reminder: most of those boats were local fishermen from Britain because Churchill didn't give a shit if his people lived or died. He's also responsible for causing a significant amount of damage in the Blitz becsause he was using ship's cannons to make it look like he was trying to shoot down Germans, and the shells just fell back down on to London.