If what they say in the memo is true, and by the domain name (an email marketing service, and not their official site?), it seems like an individual email, and not a general public message. Maybe they're just running customer's emails through a service like haveibeenpwned, and emailing the ones that return results. Apparently several major UK services have had account leaks recently, and I bet Domino's is an easy target for fraud.
I don't know anything about the company/CEO's policy, but I worked as a driver for them beginning around ~2011, and I'd have to say, they really had their s--t together on the tech front. For example, the "Pizza Tracker" is entirely real and accurate (which always amazes my friends), it's actually just a side effect of the system they have to track inventory and paying employees (an employee has to enter their ID at each station and select and order. So maybe Henry isn't actually the person doing the "quality check", but he's the person who punched in his ID and approved it). I worked at a few less experienced delivery places afterwards and the experience was just awful comparatively.