I think the word "wasted" has connotations that were not what Obama was aiming for. It makes you think of throwing something in the garbage. I think the phrase "needlessly gave their lives" would have been more accurate. It indicates, perhaps, an overabundance of generosity on the part of the soldiers.

While from an objective point of view the results may be the same, the two turns of phrase give very different intimations of the subjective meaning: The first, is that of the suicide, or the O.D., the second that of the fireman who dies in a burning building trying to rescue someone who has already perished.

So apologizing for that choice of words is fair, and does not detract at all from Obama's overall position against the war.