Also, by definition, "having a disability" implies being "disabled" in some degree.
That said, calling all people with disabilities categorically "disabled", while lexically and logically correct, does carry a clearly inaccurate and prejudicial -implication- that a person with a disability is somehow -less capable-. In this, giraffe is correct, that the use of "disabled" in this way can easily convey an inaccurate connotation of reduced capability, an thus its usage in this way is both unenlightened and potentially prejudicial - but I could hardly put it into the same category as a racial slur, which is clearly intended to diminish or marginalize.