I only know RL as a right-wing-shock-jock-global-warming-denying-nutter; if you doubt the latter, RS provides a delightful example of his crass ignorance and willingness to fall for anything that leant his way. But "environmental issues" is only a small part of his Wiki article, so clearly I've seen only one facet.
However we can tell he's not really famous, because I never troubled with him here on this blog; I think in GW terms he has long been a has-been; he got more mentions in sci.env days, perhaps.
The best defence I can find from vaguely reliable sources is he was the quintessential American entertainer by Dominc Pino. That article doesn't really even attempt to defend what he said in any serious terms, and just regards it as entertainment. Which is probably correct: as the RS example shows, he was lamentably ignorant of science, and I've no particular reason to think he was any better informed on anything else; but that didn't matter to his large audience, because people want to be entertained. In the end, if forced to defend him - which I'm not, so I won't - I'd blame Dumb America. You get the right-wing-global-warming-denying-nutters you pay for.
* What do prime-age ‘NILF’ men do all day? A cautionary on universal basic income
* Rush Limbaugh galvanised and embodied the modern American right - The Economist doesn't mention GW either.
* How the Feds Gave a Competitive Advantage to Conservative Radio by David Henderson
* Myth or Measurement: What Does the New Minimum Wage Research Say about Minimum Wages and Job Loss in the United States?
* Terence Kealey on the British ARPA by Alberto Mingardi
* One hundred years of solitude by Scott Sumner
* What I worked on - Paul Graham