Eh, I don’t think it’s be a big deal. Slap a giant warning on it, all good. Super common on all sorts of platforms. Anyone trying to claim their encryption doesn’t work because they have a (scarily labelled) option to disable it can be easily demonstrated to be disingenuous.
And worst case if someone does disable it but doesn’t implement their own then their email I just falls back to… the same as any other platform.
They might not want to take the time to build it, but I think what this dude is asking for is a totally reasonable thing.
*Normalising
Denormalising is the other way around, ie accepting duplicated or less than optimally organised data for some other reason (eg for performance or to reduce complexity for your filthy human brain - but usually performance)
Sorry I know that’s a very minor nitpick.