Anyone recommending a part Beagle as a family pet is either mad or dishonest, most families just want a healthy pet and I don't think a Childs mag that does articles on dogs not totally suitable as just that, be they cross or not is responsible or promoting responsibility.
It would be just as irresponsible to promote pure Beagles in a Childs mag.
Articles on pets suitable for families I don't see harm in, although CL got it right there too, kids will nag for what catches their eye and parents do need to say no until a child is old enough, and be prepared to step in and keep the pet if it is still alive when the child leaves home.
A suitable pet is a great thing for a child, and to rear a child without that child ever owning his or her own dog is a sad thing to do. That is if the child wants a pet of course, some don't.