Howard Stern would get bigger ratings from people who hated him and would listen to what he had to say next to get more offended by it.
That is not true. Stern had a relatively narrow cume, but huge AQH listening. The listeners were pretty much 100% fans. A hater might have listened a couple of times to see what it was like, but the core listeners listened 4 to 5 times a week for several hours each day.
Nobody goes to jail because they want to. Nobody listens to a daily long radio show every day if they hate it.
And Stern haters definitely did not write "Howard Stern Show" in ratings diaries as that would seem to them like an endorsement. The report you reference is obviously written by someone with zero understanding of radio and ratings. And remember that Stern himself said many provocative things to reinforce his image.
Does that same idea apply to Fox News ratings. How many viewers agree with their view or just watch to see what they will say next even if they think their ideas are wrong. Are CNN and MSNBC too tame for their core audience.
The vast majority of viewers, and those responsible for nearly all of the viewing time, are partisans.
The figure for Fox the State of the Union viewership was about 12.5 million according to reports. That is not even 5% of the adult voting age population of the US. More people watched, in total, the traditional networks and other distribution systems.
In the last presidential election, there were supposedly 235 million voting age persons, and 54% voted. So, adjusted for slight population increases, 12 million is really a tiny percent of the population... and the total viewership of 37 million everywhere is only about one in every 8 voting age Americans; most people did not watch. And a percentage of the watchers were below the voting age, too.