OP started a conversation based on the premise that there are right and wrong ways to design a user interface. If you're going to say it's really just a matter of personal preference, that's fine, but that's not an argument for one side of the original debate, it's a choice to pass up on that debate and have a different conversation altogether.
> Most programs which support rich text copy-pasting have "paste with formatting" versus "paste text only" options, with the ability to change the default.
Does Google Docs have these features? If so, how do you change the default?
> If an application doesn't, that's the fault of that developer, not the OS semantics.
If we accept that argument (which as it happens I don't), it's not an argument in favor of current OS semantics, it's an argument that OS semantics doesn't matter and we shouldn't be debating it in the first place.