An education is only as good as the teacher. A good teacher, be it in a school or at home, is priceless, but for home educators the potential pool of inspiring teachers is rather small. And, sadly, I have met quite a few rather dim people who don't seem to realise that education is a full-time occupation and not simply a matter of plonking the kids in front of the PC or TV while they get on with other things. In my view, if you couldn't cut the mustard in a classroom you shouldn't be teaching at home.
The sort of attitude shown by the reaction to the NSPCC's comment is one that I've come across here in West Wales (where home education is very common among counter-cultural types, downsizers and would-be hippes) - a lot of parents seem to be paranoid about any LEA or social services involvement.