Except that it is not necessarily the school's responsibility to ensure that every student leaves being well versed in how to operate a computer. ICT is there to serve as a platform to pick up 21st century skills. If learning how to operate a PC is the biggest stumbling block, then one of the solutions would clearly be to either use a simpler OS, or even a more intuitive device like the ipad, where anybody can just pick it up and start using it within 5 minutes.
This is arguable. I hate to keep revisiting the same argument but this could be perceived as saying it's not the schools responsibility to teach a child to read. You can't just teach someone using children's books until they are 18 and then send them into a world which they then can't deal with.
I think it all depends on where you draw the line on what you want schools to teach children.
One slightly different point I'd like to make is that there is a danger when you use simpler and simpler OSes to teach, as there will be a shortage of young people with the skills or interest to go into software development, a problem that hopefully will be addressed by the Raspberry Pi foundation and similar projects!