didn’t Hansel say the oven caused the burns?
That’s one of the corrections Hansel made to Henry’s book in in 7×16 “Breadcrumbs”. The idea that the killer was correcting that particular story was a major clue toward identifying him. You’re right, it doesn’t fit with what we saw in 7×17.
I think we could stretch the interpretation of that line so that it just means “I really hate witches”, and that Hansel is choosing to remember his story inaccurately in a way that helps him justify his killing spree. Or maybe he’s just trying to be poetic about metaphorical flames scarring his soul; he works in the music industry, so maybe he tends to think in lyrics.
Hansel would have made a good main antagonist for this season. He’s a counterpoint to his good friend Henry, who could have been the primary protagonist. And, although I’m certainly not condoning murder of murderers, I’m glad that the show is at least acknowledging that evildoers such as the show’s witches can’t expect to avoid punishment by simply choosing to not do evil anymore. This could have given the show a depth that it’s been lacking this season.