They should show and broadcast nothing but art and science and classical music that wouldn't appear or be heard otherwise.
If they can't be depoliticized by killing their "news" departments, then defund them in toto.
Actually it would be on cable. PBS has programs like NOVA because the programs are subsidized with taxpayer dollars and are nearly free for them.
Take away PBS free programming and it would probably be done better by private production companies.
In all truth, if any of the programming had any real social worth or demand, they would not require the receipt of tax dollars to begin with.
It is not the responsibility of taxpayers to fund something that only a small sector of our society wants. Please note that I purposely did not say “needs”.
If you want to fund Nova or whatever else, you are perfectly free to do so with your own money. Please have at it.
NOVA broadcasts its share of globalony propaganda.
Even their "do-it-yourself" shows like This Old House and Ask This Old House push those curly-Q compact fluorescent light bulbs like they're the saving grace.