I find that this is not the case with "Weird Al" Yankovic. First of all, he doesn't only do parodies. He has a fair bunch of original songs, but most of them are still parodying a certain band or musician's style. Those are a hundred times better and interesting, in my opinion. Of course, it's the parodies that made Al what he is today, so I'm not saying they're any less important or anything.
He also gets praised for having a clean sense of humor, but he has his adult moments, of course. This album is a perfect example of that. It's dripping with black humor and sarcasm, and I love it because of that. This is Weird Al at his weirdest and wildest.
The parodies include "Ricky" (an I Love Lucy homage set to Toni Basil's "Mickey"), "I Love Rocky Road" (one of his many songs about food, this one set to Joan Jett's "I Love Rock 'n' Roll"), and his classic "Another One Rides the Bus" (a caricature of public transportation set to Queen's "Another One Bites the Dust").
This is the only album where Al plays the accordion on all the tracks, and the parodies sound much more different than the original songs, but I think they sound much more interesting this way. But that's just my opinion.
Al's originals are awesome. "Buckingham Blues", "Happy Birthday" and "I'll Be Mellow When I'm Dead" are my favorites because of their extremely sarcastic lyrics, and also because they sound kickass. "Mr. Frump in the Iron Lung" is really neat as well.
Even if you're not much into parody (like I am), or if you just don't like parodies at all, I recommend you give this album a try, just for the sheer weirdness.