The lie is that they claim that they released their OpenGL ES (and more other APIs) implementation and the the Linux kernel parts under a BSD and/or GPL licence (my summary). If they said they released the shim which calls to those implementations which runs on another processor and which isn't in that release I wouldn't call them liars, but only applaud their step towards more free software.
To verify my summary look at the image in their post: http://www.raspberrypi.org/wp-content/uploads/2012/10/Arc...
The block they label OpenGL ES is actually only a shim but nowhere in the post or the image do they say that.
The post does not mention that the release doesn't allow one to modify the OpenGL ES implementation.
In the comments the lie goes from omission to denying the truth: http://www.raspberrypi.org/archives/2221#comment-34981
"Isn’t the userland code you just made available the simple shim [...]" - Luc Verhaegen
Replying to that:
"No. There’s some microcode in the Videocore – not something you should confuse with an ARM-side blob, which could actually prevent you from understanding or modifying anything that your computer does." - liz (AFAIK officially speaking for the Raspberry Pi Foundation)
That is simply not true. Yes it is only a shim and yes it actually prevents one from modifying some part of what your computer does.
In other comments asb (the one who did the original post) side steps the issue when confronted, but sadly never actually acknowledges that that which was released as free software is not the full implementation but a shim.
I like that they released the shim. I don't like being lied to and I don't understand why they would do that in this case. What do they have to gain from this?