Words don't need to be trademarked to have a meaningful definition.

Who gets to decide the definition? The blog uses the definition "Note that when we say 'free' here, we mean free as in speech, not free as in beer," but I would argue "free for non-commercial use" licenses _are_ inherently free as in speech, but not beer.

> Who gets to decide the definition?

The FSF. Their definition of Free Software is the accepted one. The blog post links to it.

> I would argue "free for non-commercial use" licenses _are_ inherently free as in speech, but not beer

No, when software is free as in beer, that's used to mean that it can be obtained free of charge.

Software whose licence prohibits commercial use is by definition not Free Software, following the FSF definition, as this violates Freedom 0.

> The FSF. Their definition of Free Software is the accepted one.

Anyone can create their own organization with their own list of violations.

I happen to be in agreement with the FSF on most points, but not with regards to non-commercial licenses.

But the freedom of speech applies even to commercial speech.

Right. The terms power and force are not trademarked, but anyone who tries to argue that physicists are using these terms incorrectly can expect to be laughed out of the room. That's as it should be.