The FSF has been very vocally for APIs to not be copyrightable. They've filed amicus briefs to that effect.

Edit: also why do those emails matter? The facts of the case aren't dependent on them. There's nothing wrong with a company looking to build a semi interoperable replacement to avoid license fees. That's why sun bought and continued development on OpenOffice; they figured out that was cheaper than the MS Office fees at their scale.