[EdwardMSmith]

I'm not a lawyer either, but isn't the word "claim" a term of art in law. Doesn't it have a specific meaning distinct from the common usage?

[teraflop]

"Claim" has a specific meaning in the sense of the invention "claimed" by a patent. But Facebook's patent grant is clearly not using it in that context: "any claim (including by filing any lawsuit, assertion or other action)".

[ralmidani]

And a good reason for someone to claim a patent is invalid is being sued for violating that patent.