-- Humor?

A colleague and friend just pointed this out to me: Look at the Library of Congress Subject Headings for a book by Ann Coulter. Let's take the book If Democrats had any brains they'd be Republicans. This classic (classy?) text has chapters entitled "Foreigners, or the 'non-soap oriented'" and "Guantanamo: room service, I'd like seventy-two virgins, please." So, what did the catalogers at the Library of Congress have to say about this book? Well the LCSH are:
Liberalism -- United States.
United States -- Politics and government -- 21st century.

Ok. Let's look at another Ann Coulter publication. How to talk to a liberal (if you must) : the world according to Ann Coulter. LCSH for this one?
Liberalism -- United States.
Mass media -- Political aspects -- United States.
United States -- Politics and government -- 1989-.

BTW - I'm taking these directly from the loc.gov library catalog.

Now, for comparison's sake, let's look at Al Franken's book Lies : and the lying liars who tell them : a fair and balanced look at the Right. LCSH for this one?
Conservatism -- United States -- Humor.
Right and left (Political science) -- Humor.
Truthfulness and falsehood -- Political aspects -- United States -- Humor.
Rhetoric -- Political aspects -- United States -- Humor.
Mass media -- Political aspects -- United States -- Humor.
Political culture -- United States -- Humor.
Political satire, American.
United States -- Politics and government -- 2001-2009 -- Humor.

I'm not sure what to make of the LCSH for Michael Moore. His Dude, Where's My Country?
War on Terrorism, 2001-2009.
United States -- Politics and government -- 2001-2009.

But Moore's Stupid white men-- and other sorry excuses for the state of the nation! again has "Humor" as qualifier for the LCSH:
American wit and humor.
United States -- Politics and government -- 2001-2009 -- Humor.
United States -- Politics and government -- 1993-2001 -- Humor.
United States -- Social conditions -- 1980- -- Humor.

Is LC implying that Ann Coulter's books are some how more legitimate than Al Franken's? Or are they saying she's just not funny?