My sense of humour might be miscalibrated, but I thought this was a piss-take of the very earnest open letters you see all the time, written as if they are actually addressed to someone that will actually read them.

This is just a weird way of pointing out that they don't have a NDK on the new Windows Phones, and if they did then Firefox would get ported (with some gratuitous plugs for ongoing work on competing platforms).