The Fair Use Doctrine of copyright law states that there is no copyright violation when a necessary portion of a work is presented as part of commentary or criticism of that work. Copyright restrictions on a book cover are further weakened by the fact that a cover is meant for exposure and advertising; it’s hard for you to argue that someone is violating your copyright by advertising your wares.
I am an Amazon and Smashwords affiliate; the links run directly to retailers whom you have authorized to promote and vend your books. So if you object to being featured on Lousy Book Covers, you aren’t legimitately objecting to the exposure as such, but to the negative characterization which Lousy Book Covers entails. (Because, really, would you be up in arms if your book showed up on a website called Terrific Book Covers?) That means that what you want silenced is my opinion. Sorry, that ain’t gonna happen.
Also, before you make complaints and try to get your book cover taken down, please google “the Streisand effect.” It was a couple of authors shouting “copyright violation!” that led to the original tumblog of this site going viral and being featured by Andrew Sullivan, Publishers Weekly, the UK’s Guardian, io9.com, HuffPo… Probably not the publicity those authors wanted.
Speaking of copyright, because I have nowhere else to stick this: The goat image in the header is courtesy of Matthew Schultz, and is licensed by a Creative Commons attribution license.