
No-one is suggesting that *only* OSS is used in schools and education, but that it *should be* used. The fact is that the opposite is largely the case at the moment: *only* propietary software is used.
And the point Diana Artemis made (if you had actually bothered to read what she wrote) was that free (as in freedom) software can be examined, modified and improved by students so they learn, as opposed to M$ free (yeah we'll let you download it and use it in strictly defined ways and if you do something we don't like we'll see you in court) software.
As for your point about using software that is most commonly subject to attack, that is a red herring in this case: for students it is more important to learn *why* a bit of software is crap, not just that it *is* crap.