Izzy had tried to ruin both their lives, had tried to kill Stede or get him killed on multiple occasions. The look Stede made at the mention of what he'd done was just another of their differences: Edward had been a pirate for a very long time, he had his own rules and always had done, but he'd also had to learn to be ruthless even before he'd gone to sea. Stede's distaste for real violence... it made for a terrible pirate overall, but it was something Ed didn't want to see him lose all the same. There were plenty of ruthless pirates and only one Stede.
The soft smile made him feel a little more secure in this, even if he was still unsure about what exactly they were doing.
"Well, that's a leading question if ever I heard one," Edward replied, returning the smile before taking a sip of his tea mostly to have something to do with his hands. "What did you realize?"