"Sue us and your license is revoked" is quite a reasonable provision, IMHO.
Edit: if you're going to down-vote, at least read my clarification below.
Edit: if you're going to down-vote, at least read my clarification below.
Why would I build on something that lets the owner act against me with relative impunity (assuming the software is something critical)?
Furthermore, I think the problem is not here, the PSF clearly made a mistake by not registering the name (it's not a matter of 'bad law'). If we apply your solution, then it would mean that a company which does not use Python can still ask to register a global trademark named on the term.
You acquire some pretty reasonable rights in a trademark by virtue of use alone.