"decimate has been used since time immemorial to mean to lay waste to, to severely damage, to annihilate or to devastate, without particular reference to one-in-ten." - Steve Shaw

No it hasn't. That meaning is modern over-emotive twaddle.

As a means of punishment and enforcing discipline it was measured so as NOT to affect the fighting capability of the unit - NOTHING even remotely close to:

- Lay waste to;
- severely damage;
- annihilation (total destruction);
- devastation.