That's an interesting interpretation of the sentence : The paper declined to run either because of a policy not to publish form letters.
Not printing mass-produced form letters and not printing letters home from soldiers are two different issues. Point to me in that sentence, or the article, or anywhere, where the Olympian states it's policy of not printing soldiers letters.
The article makes it clear, in fact even talks to several (6, I think)of the soldiers who's name's were on the letters, and none of them admit to having wrote it (even if they agreed with its sentiments). Which would make it a form letter. Which would make it ineligible, according to the paper's guidelines, to be printed on the editorial page.
And besides, as the F-9/11 reviewer pointed out below, interviews and letters from individual soldiers just add up to a whole lot of anecdotal evidence. Which can be useful, but doesn't generally make a case all by itself. You could find, I'm sure, a dis-satisfied soldier for every soldier who believes fully in his mission.
As far as the anti-war 'jab' at the end, that was the word's of one of the Mother's, not the paper's. If they truly wanted to be liberal, they probably wouldn't have included the fact that the soldiers agreed with the letter, even if they didn't write it. Michael Moore, for example, might have left that bit out.