I see that Joe Kernen is claiming that Paul Krugman called him or his colleagues a zombie, and that he thinks Krugman calls anyone who disagrees with him a zombie. He is calling for an apology.
What Krugman was referring to were zombie ideas, that is, ideas that have been proven wrong over and over, so you would think would be dead by now, yet they keep coming back. Zombie is a metaphor here, one that Krugman uses often, for ideas that should have been long since discredited, yet keep getting spread by the Joe Kernans of the world. And yes, Mr. Kernan was spouting zombie ideas on this program, so the characterization was certainly apt.
That Mr. Kernan could not understand the simple concept of what the expression "zombie idea" means is indicative of Mr. Kernan's general inability to comprehend economic concepts. And if anyone should apologize, it is Mr. Kernan for his failure to allow his guest on the program time to explain his ideas: almost every time Mr. Krugman began an explanation, he was interrupted by hectoring from Mr. Kernan.
Mr. Kernan followed up with these tweets:
Krugman blogs "Zombies on CNBC" after interview. Dismissed every fact he didn't like as "myth".
Said 50 percent of GDP was the acceptable level of US government spending. Best economy in his words a "Free Market Welfare State"
So when Mr. Krugman correctly points out that one of Mr. Kernan's ideas is a myth, Mr. Kernan's reply on his tweet is that his idea is a "fact." A perfect illustration of clinging to a zombie idea.
And Mr. Krugman did not, as Mr. Kernans tweet suggests, say that 50% of GDP was THE acceptable level of government spending: he said that he would be concerned if it were to get above 50%, but Mr. Kernan did not give him a chance to explain what he thought an appropriate percentage would in fact be. I imagine Mr. Krugman would have pointed out that the percentage of government spending would depend on the business cycle: a lower percentage when the economy was expanding well, a higher percentage during depressions to stimulate the economy back to growth. Again, a simple concept that seems beyond the capability of Mr. Kernan to grasp.
Update: for a model of how an interview should be conducted, see here and here.