I (not a lawyer) understand copyright law to mostly prohibit us from copying the spec document without permission, and then the license provides permission for

I (not a lawyer) understand copyright law to mostly prohibit us from copying the spec document without permission, and then the license provides permission for some copying of the document. I'm pretty sure the authors really want to prevent competing implementations that make money for someone else, and the wording expresses their intent. I believe that copyright on the document won't let them stop a company that can afford decent lawyers from implementing the spec, but it certainly doesn't make me any more likely to touch anything related.