I think Amazon made a bonehead move, and I've enjoyed seeing them get some bad publicity. However, I wonder how many people use this tool simply so that they can view library books or purchase ebooks from sources other than Amazon.
My guess is that most people use these tools in conjuction with the mobidrdrm tool to strip the DRM. This doesn't mean I think people are doing anything wrong. There are legitimate reasons for stripping the DRM that have nothing to do with piracy. Foremost, is that stipping the DRM allows us to transfer books we have purchased to other readers that may come out in the future. Who wants to be locked into the Kindle forever? Is this against the "law"? Yes, I'm pretty sure it is, but I try to live my life by what is right and wrong, not what is lawful and unlawful -- although I'm not admitting to anything.