Surely there exists better terms than an explicit blacklist. I see this as a social weakness in GPL and other open source. GPL wanted to restrict people from profiting without contributing back. Now they profit and attack other projects.

What about this: GPL is supported by the FSF. Add a term which allows license use as long as no other projects explicitly supported by the FSF are attacked. (For some definition of attacked, supported,...)

Everything remains open, yet the FSF/OSI gets ways to fight back against egregorious takedowns.

Even just terms revoking the youtube-dl license the RIAA has (because you can bet one of them has used it), would be a step forward.