My understanding is that the MIT license - used by lots of projects, including eg Angular - doesn't afford any patents protection at all. So, would you criticize those using the MIT license more than Facebook?
I feel it's a little like this: https://www.xkcd.com/463/. Yes, the new license is providing explicit guarantees that do not exist in the MIT license. But... I'm not sure I like the thinking behind it when other licenses already address this in a fair way.
The MIT license says plainly that you have the right to use the software without restriction. To me, a layman, it would seem contradictory and unfair if the author later claimed that they held previously unmentioned patents that restricted your use of the software.