His legacy is still more complicated than I have described here; try his Wikipedia entry (most of which I wrote).
And how and why do I know all of this? I never heard of Lassiter until 2004, when I stumbled upon the legendary 1987 call from an outraged listener that's become known as the Mr. Airstream call. As Lassiter says during the call, it may be the best call any call-in radio program ever received.
I laughed so heard that I Googled his name, found more recordings, and wound up becoming a connoisseur of his career. Then he started his blog, which was followed by a fan site of his old airchecks -- how many call-in talk show hosts have a cult built around their old recordings?--and I became a true disciple. I don't know how Lassiter would feel about my calling myself that, but there's no better way to say it -- the more I heard him, the more he became a mentor, a guru, to me.
I've thought a lot about why. Why do I take such inspiration from a man ranting about the issues of the day in 1988? Or branding as "subhuman pigs" elderly retirees who, today, are long since dead? What could these ancient recordings have to say to me?
I think it started because he reminded me of a former mentor: a man from my hometown who also had been in radio, had a similarly deep voice and gruff demeanor, and had a trademark beard. (This guy looked nothing like Lassiter, but I picture him talking half the time I hear Bob.) But that connection faded quickly. My hometown the guy was an asshole, pure and simple. Lassiter often portrayed himself as an asshole, but he was also incredibly thoughtful and sensitive and hammered at people to THINK. He could even be effusive and sentimental, talking about his relationships with his wife, his mother, even his dogs.
Lassiter's thoughts and lessons were timeless. He often discussed things like religious hypocrisy and Biblical self-contradictions, racism, sexism, political lies and rhetoric, and--especially--people's tendency to blame everyone but themselves for society's ills. ("Whatever problems America has can be traced back to one specific group of people: Americans! You and me!") Even if these things are being discussed in the context of Reaganomics or Clinton policy, or Jimmy Swaggart, or the O.J. Simpson trial, Lassiter is getting at universal truths, things that have always and will always be problems, and how we might understand those things and maybe even work to get past them. Which is, of course, the definition of timelessness.