It's not a copyright license. It's a patent grant/license which is completely independent. This matters for several reasons, including when just saying "license", this usually means a copyright license.
If this patent grant get's revoked, you are back to simply using the BSD license with no patent grant. I've read so many people say "you'd have to stop using react if you sued facebook", uh, no, you'd have a bsd license with no patent grant like you probably do with tons of other free software your company uses. Clearly, people should be complaining about that if they are complaining about this, but the misunderstanding and misinformation is really strong. If you believe software patents are universally bad, like many people including me, then it is clearly better using the MIT/BSD license alone, which gives you zero patent rights, you are simply infringing and waiting to be sued. I have no problem with it. https://www.gnu.org/philosophy/software-patents.en.html.
I think you're missing the plot. Currently, there is a big philosophical debate on whether OSS licenses like the BSD include an implicit patent grant. When Facebook explicitly includes a revocable patent grant, your argument of the BSD license "with no patent grant" is self-fulfilling. But if the PATENTS file had never existed, then what you have is "a BSD license with a potentially implicit patent grant", which has never been tried in court so could set a precedence, but is waaaay better for the consumer than a "BSD license with no patent grant because that patent grant has been explicitly granted and now revoked".
To me it's sort of a toss up between these two scenarios. Implicit grant that has never been tried in court vs explicit grant that only gets revoked if I initiate a patent war?
In both scenarios you have a patent grant before going to court over Patents. The difference is that, in one scenario, you no longer have a patent grant once you go to court. In the other scenario (where PATENTS file never exists), you may still have the patent grant after court.
I've seen it pointed out before though that it would fall back to just the BSD license and others countered saying that was definitely not the case. It seems to be yet another fundamental thing about this that isn't clear or agreed upon at all. Still, your point is important and I hope people read it and consider it.
Also by "license" I meant the "BSD + Patents license" as the Facebook writeup put it.
"...definitely not the case." Citation needed, reasons required, etc. The patent license says nothing about terminating the BSD license. Neither refers to nor affects the other. Without a good legal argument, one must assume that the BSD license applies whether Facebook is being sued over a patent or not.
That answer only addresses the "copyright license", others argue that plain BSD is a "license to use".
If BSD is a "license to use", then it is implicitly a copyright license _and_ a patent licence.
Assuming the above, the argument goes that the implicit patent license in plain BSD is overridden by the explicit patent license in BSD+Patents, and that the explicit one is much more restrictive than the (unwritten) implicit one.
It's not a copyright license. It's a patent grant/license which is completely independent. This matters for several reasons, including when just saying "license", this usually means a copyright license.
If this patent grant get's revoked, you are back to simply using the BSD license with no patent grant. I've read so many people say "you'd have to stop using react if you sued facebook", uh, no, you'd have a bsd license with no patent grant like you probably do with tons of other free software your company uses. Clearly, people should be complaining about that if they are complaining about this, but the misunderstanding and misinformation is really strong. If you believe software patents are universally bad, like many people including me, then it is clearly better using the MIT/BSD license alone, which gives you zero patent rights, you are simply infringing and waiting to be sued. I have no problem with it. https://www.gnu.org/philosophy/software-patents.en.html.