I never said that you could lose your license for competing against Facebook, I said that you could lose your license if you have a patent and assert it against Facebook if it infringes. This is the patent grant from React, which is identical to the grant in the post's repo as well. The language in the patent grant is pretty clear and doesn't mention anything about React specifically:
The license granted hereunder will terminate, automatically and without notice,
if you (or any of your subsidiaries, corporate affiliates or agents) initiate
directly or indirectly, or take a direct financial interest in, any Patent
Assertion: (i) against Facebook or any of its subsidiaries or corporate
affiliates, (ii) against any party if such Patent Assertion arises in whole or
in part from any software, technology, product or service of Facebook or any of
its subsidiaries or corporate affiliates, or (iii) against any party relating
to the Software. Notwithstanding the foregoing, if Facebook or any of its
subsidiaries or corporate affiliates files a lawsuit alleging patent
infringement against you in the first instance, and you respond by filing a
patent infringement counterclaim in that lawsuit against that party that is
unrelated to the Software, the license granted hereunder will not terminate
under section (i) of this paragraph due to such counterclaim.
Also, your link doesn't actually dispel any fears I have. It specifically doesn't mention about if I sue Facebook for patent infringement if I have a valid patent that Facebook infringes upon, which is the main basis of my argument and worry.
Both you and grandparent are wrong. I have consulted with lawyers on this (and the language is pretty clear as well). If you initiate a patent lawsuit against FB on any grounds, you lose patent protection for this library (or React, Reactive-Native, etc -- they share the same patent licensing terms).
If you counter-sue FB after they have initiated a patent suit against you, you are ok, as long as your counter-suit does not cover patents you were licensed via using React, Yoga, etc.
This type of patent language is called a "strong patent retaliation clause." What you are describing also exists (Apache uses it) and is called the "weak patent retaliation clause." They are not the same.
If I am using React/Yoga/etc, and have a patent on FooTech, and Facebook starts using it tomorrow without license, and I sue them, then I have tripped clause (i).
The license granted hereunder will terminate, automatically and without notice, if you (or any of your subsidiaries, corporate affiliates or agents) initiate directly or indirectly, or take a direct financial interest in, any Patent Assertion: (i) against Facebook or any of its subsidiaries or corporate affiliates
At that point, I am infringing any patents that FB have on all of {React/Yoga/etc}. Thus opening myself up immediately to a counter-patent suit, even I infringe no other FB patents.
tl;dr any patent suit initiated by me (troll or legitimate), revokes all the patent grants for every FB product using this license.
IANAL but isn't the text quoted above also saying that except if initiated by Facebook suing you over a patent first, any patent lawsuit against facebook will terminate your license? It's listing "(i), (ii) or (iii)", not "(i), (ii) and (iii)".
The license granted hereunder will terminate, automatically and without notice, if you (or any of your subsidiaries, corporate affiliates or agents) initiate directly or indirectly, or take a direct financial interest in, any Patent Assertion: (i) against Facebook or any of its subsidiaries or corporate affiliates, (ii) against any party if such Patent Assertion arises in whole or in part from any software, technology, product or service of Facebook or any of its subsidiaries or corporate affiliates, or (iii) against any party relating to the Software. Notwithstanding the foregoing, if Facebook or any of its subsidiaries or corporate affiliates files a lawsuit alleging patent infringement against you in the first instance, and you respond by filing a patent infringement counterclaim in that lawsuit against that party that is unrelated to the Software, the license granted hereunder will not terminate under section (i) of this paragraph due to such counterclaim.
Also, your link doesn't actually dispel any fears I have. It specifically doesn't mention about if I sue Facebook for patent infringement if I have a valid patent that Facebook infringes upon, which is the main basis of my argument and worry.