The key word there is "competent." With all due respect, I don't know if the UK's teacher cert standards are the same as ours, but there are a majority of high school teachers in ALL subjects here in the US that I wouldn't trust to teach kids to wipe their arses.
That may well be so: but there remains rather a large difference between a government instructing you to do something, a government instructing you not to do that thing, and a government leaving you free to do or not do that thing as you see fit. I’d need a lot of persuading that the third of these options is not to preferred, in this as in most other circumstances.