I think I'd give the benefit of the doubt.
I'd explain that puppies from reputable breeders are not usually available at the last minute as it takes considerable planning and then there is waiting for the bitch to come on heat, and the time it takes for puppies to gestate. But if they're willing to wait and provide some more details about themselves - I could point them at a breeder who is planning a litter to see if they have anything suitable.
So they probably wouldn't get a puppy for christmas from a responsible breeder - and I'd provide them with the link to the RSPCA responsible breeder list of attributes, and I'd also mention some of the legal requirements eg microchipping, vaccination, and 8 weeks old. And if it's an ANKC breeder - ANKC registration - which is not the same as council registration for a puppy farm business.
I probably wouldn't suggest "rewording" - given your experience and some experience the responses of people who join here looking for instant puppies - I'd just go for education aimed at filling the gaps in knowledge exposed by their request,and let them figure out for themselves that their email needs to contain more info and/or a rewrite with a greater sense of patience.
The whole way good quality puppies are acquired - has changed in the last 20 or 30 years pretty much. When we got our first dogs - we'd never heard of rescues. So we had a fairly random collection of BYB / Farm bred bitsas and ANKC bred not the breeder's fav puppies.