Again and forever:

These fights stem from usage of a proprietary definition of Open Source (the OSI's). Obviously the definition doesn't resonate with DHH, and he uses the words 'open' and 'source' colloquially. Open, as in a book or a window, source, as in the thing that gets compiled into bits and bobs that run on computers. You wouldn't jump on someone's "open letter" to city hall because of a lack of freedom to fork it.

This could stop if people capitalized their reference to Open Source, which is standard English treatment of proper nouns. Unlikely to happen though, because insisting that "my definitions are your definitions" seems to be a primal tribal instinct for humans.