In the case of the Canadian meal, the image isn't really representative of the variety of meals that exist. (See http://en.wikipedia.org/wiki/Individual_Meal_Pack for the list of entrees in 2005.) Certainly meat features in the majority, but every soldier can expect a vegetarian meal with some frequency. Choosing her example meals, I think it's possible that the article's author was somewhat biased toward names like "Swiss steak with Spanish sauce" and away from pasta, baked beans and other commonly canned foods.

It's already been suggested that providing vegetarian meals is a logistical nonissue. (Canadian soldiers are also entitled to Kosher and Halal meals, and I can't imagine that that's uncommon.) But it's easy to imagine military professionals arguing the opposite. Logistics, tactics, and esprit de corps are used to justify several kinds of bigotry and obstinacy in Western militaries. It seems to me that, as a rule of thumb, legitimate military concerns do not easily justify lower standards of tolerance, human rights, or, (as Julien Assange will agree) openness. Canada has rejected at least two of these arguments experimentally by allowing openly gay service members (unlike the US) and by permitting women to serve in every trade (unlike the US and the UK).