Because it works wells enough for education purposes and would help prepare them for computers that many of them would encounter eventually. Sugar was well intentioned wankery. You could have had special use case software for off the grid lessons, but giving them all a bizarro UI that wasn’t like anything anyone had ever seen before didn’t make a whole lot of sense. I’d say it was one of the big reasons OLPC failed. Also, had they forked off of existing DE/WM around at the time it would have been less buggy and would have involved less effort on their part. Sugar dropped me to console more than once, and I don’t expect most students or their teachers knew what to do besides reboot and probably lose work at that point.