The core mistake of the present Sugar approach is that it couples phenomenally powerful ideas about learning — that it should be shared, collaborative, peer to peer, and open — with the notion that these ideas must come presented in an entirely new graphical paradigm. We reject this coupling as untenable.
Choosing to reinvent the desktop UI paradigm means we are spending our extremely overconstrained resources fighting graphical interfaces, not developing better tools for learning. … It is most important to recognize that the graphical paradigm changes are inessential both to our core mission and to the Sugar core ideas.
On the other hand, I think the first half of his post obscures more than it reveals. I'll be happy if I never have to listen to programmers point/counterpoint on "constructionism" again. It is difficult to calculate how much Seymour Papert's incapacitation crippled the heart of OLPC's mission.