IANAL but my interpretation of the clause based on comments / links is that it aims to protect Facebook by reducing patent lawsuits in general. If that is actually valid, I would expect there would be many people who are for the terms internally. Am i fully misinterpreting here?

Just use Polymer, vue or something else without that problem :-)

Facebook patents that apply to React will also very likely also apply to Vue or any other virtual DOM library. Using Vue makes you more vulnerable, not less, since you no longer have the protection of the React.js patent grant.

You made this assertion before, but it's wrong and dangerous. Without knowing what the patents are, you cannot possibly say whether or not OTHER technology is infringing on it. It is especially bad considering you are not a lawyer, nor have professed any familiarity with the patent process.

It is a moderate, but known, amount of work to look through FB's patents, assess which are likely around React, and read through the claims. Considering it's possible, I certainly think that it's reasonable to ask you to do the work, or stop making the assertions.

But I have been told, by lawyers, never to read patents, because that could triple damages for knowledgeable infringement.

It also doesn't address potential patents that are still within the 18 month filing window and are still secret.

Then don't make the assertion.

Polymer has nearly the same provision. They're sneaky about it as it doesn't appear in the main license. http://polymer.github.io/PATENTS.txt

Not at all:

"If you or your agent or exclusive licensee institute or order or agree to the institution of patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that this implementation of Polymer or any code incorporated within this implementation of Polymer constitutes direct or contributory patent infringement, or inducement of patent infringement, then any patent rights granted to you under this License for this implementation of Polymer shall terminate as of the date such litigation is filed."

I dont see how is that similar to react. It makes way more sense and is closer in spirit to apache I think.

Yes at all:

"If you or your agent or exclusive licensee institute or order or agree to the institution of patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that this implementation of Polymer or any code incorporated within this implementation of Polymer constitutes direct or contributory patent infringement, or inducement of patent infringement, then any patent rights granted to you under this License for this implementation of Polymer shall terminate as of the date such litigation is filed."

Polymer license only concerns itself with itself. FB license concerns all patents you and FB might have in addition to patents/righs concerning the react code itself.

There is a big difference, although it might not look like that.

Read that text again... especially this part:

"against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that THIS IMPLEMENTATION OF POLYMER or OR ANY CODE INCORPORATED WITHIN this implementation of Polymer".

I know I ask much of you but you can do it. BTW. congratulations on copy pasting the text I pasted above...

I disagree.

Then it should stop you from using software from EVERY large company... many choose Apache 2, which has similar provisions which include revoking your copyright license... MS and Google both include similar provisions in most of their permissively licensed software tools/libraries.