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).
People read "Dear Steve Ballmer (mozilla.com)" and expected something more other than what they got. Even though people are smart enough to understand the context after they clicked the link and started reading, that single line is all you have to set expectations before the click, and in this case expectations were set way too high. The annoyance that causes only amplifies whatever complaint the reader has about the content.
Obviously this could have been avoided by not having a personal blog on mozilla.com, or by not writing posts like this on it, or by not submitting it to the srs bzns HN crowd (which by and large can't take a joke)--but really, a more descriptive submission title probably would have been enough.
If you click through and read the comments this seems to have pissed off a whole bunch of folk (for reasons that are still not obvious to me) from all across the net.
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).