If they conflict with RISC-V's own space, the chip can't use RISC-V trademarks.
And, of course, the RISC-V Consortium will never adopt proprietary extensions, as that goes against its core values.
Everything else matters as much as FSF point of view on something being free or not.
So that we do not have to rely on anybody's goodwill.
Just like many open core products that really need the full deal for being usable in a proper way.
Expecting otherwise is whishful thinking, or academia/maker community focus.