The definition of a patent is that you were the first and created the idea, thus, you have patented it to protect it. In essence, they are claiming they invented it
The sad part is the patent office has been granting patents where there is obviously prior art that should have invalidated the application. There's a specific patent office in TX where people file all sorts of crap because they're known to rubber stamp stuff

I know this because I was involved in a RIM case w/ a patent troll that did this...