In this case, they do have a patent.

Sure, that is the point of the original point of the article after all. I was speaking about the problem in general (I suspect most Rust projects--if not most projects in general--with this setup do not have patents).

It also requires actively persuing a patent case which may result in the patent being rendered invalid, while a termination clause for the whole license just requires a far more clear-cut copyright infringement claim (possibly achievable purely through the DMCA system, out of court). But I'm not a lawyer, maybe counter-suits are more common in such situations and so either approach is just as good in practice.