I second your call...
... on several grounds.

One of them is this bit:

it means they essentially stopped studying a subject at any depth at the age of 18 (or 17 here in Scotland.)

If you're in Scotland, and visiting Scottish schools, then why not say "17 (or 18, in other countries)" or just "17"? It would look nonsensical if somoene from England had written:

it means they essentially stopped studying a subject at any depth at the age of 17 (or 18 here in England.)

Just very fuzzy thinking, or perhaps a touch of the cringing Scot syndrome.

Oh, and on the less annoying but more pertinent points:
1. Primary teachers are generalists for a reason.
2. It is ridiculous to state that you have visited 200 primary schools in 6 months to the extent that you are able to infer a causation or even correlation between individual teachers' educational backgrounds and their ignorance; it is far more ridiculous still to add a further link to their general teaching ability.

In short, complete nonsense with a bit of national insecurity thrown in.
(snopesthetruth, Thu 15 Jul 2010, 12:59, Reply)