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Technically, this has nothing to do with the Right Hand Rule. That is just a human convention to assign a positive and negative signs to a particular direction. Electromagnetism doesn't care about our silly human notations.

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semantics vs syntax - magnets don't have hands obviously, but the metaphor holds just the same.

There is no "technically..." nonsense! It's not a human convention either - it's an anthropomorphic metaphor.

Name another animal that uses that convention.

The point is that it's not a convention - it's a metaphor, as hnriot pointed out.

It's not a metaphor.

http://en.wikipedia.org/wiki/Metaphor

No one is comparing or likening charge to some other thing. We simply give opposing charge "directions" a name. Everyone uses the name. It's a convention.

The comparison that is being made is the direction your thumb points when your fingers wrap in a particular direction. It's not merely giving it a name - it's specifically likening the vector to the relative orientation of your fingers. That's why the comparison is memorable. If it were merely a name with nothing that it is compared to, it would not be memorable nor helpful.

It does, however, exhibit the properties we use language to describe. There's a kernel of truth at the center of it.

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