Public radio's deep fried Christ

Recently a public radio station in Salt Lake City aired a skit with the following lines:

[Woman’s voice]: And now another Huckabee family recipe leaked by his
opponents.

[Male Voice]: Tired of bland unsatisfying Eucharists? Try this Huckabee family favorite. Deep-Fried Body of Christ--boring holy wafers no more. Take one Eucharist. Preferably post transubstantiation. Deep-fry in fat, not vegetable oil, ladies, until crispy. Serve piping hot. Mike likes to top his Christ with whipped cream and sprinkles. But his wife Janet and the boys like theirs with heavy gravy and cream puffs. It goes great with red wine.

Why is it constitutional for the public broadcasting radio station to use tax dollars to trash Christianity, but unconstitutional for someone to promote Christianity, for example, in a public school?

Please remember this next time you hear one of the public broadcasting stations' long, drawn-out badgering and manipulation campaigns to solicit funds from their listeners.