Human Rights for the few?

I just spotted this little gem over on the Government News Network. Apparently, the UN has just agreed a "new Human Rights Convention for disabled people". I have only one question. How can there be Human Rights that are only applicable to certain social groups?

If one buys the line of Human Rights being inalienable - which for the sake of argument I will - then by necessity, anyone who possesses the quality human is accorded all "Human Rights". However, if demarcations are then drawn between certain groups and circumstances, then you actually demolish the supposed inalienabilty of your starting assumption.