I understand the impulse to rage, "multiplayer" and "DLC" are two rage-inducing words in the gaming community right now, and putting them together doesn't exact send the best message. But I think we need to calm down and look at this in a different way. Here are the facts:
1) This is a rumor that I heard for the first time in this thread and nowhere else- we have no idea if this is true in any way. This could be complete bullshit- remember the endless rumors of multiplayer in Batman: Arkham City that only stopped when Rocksteady came out and said "WE'RE NOT DOING MULTIPLAYER, OKAY?" We must wait for Gamescom, I guess.
2) If you don't want to have multiplayer, then don't buy the multiplayer. Plain and simple. I actually think that releasing the multiplayer as DLC is a really good idea, as it allows people who want to try the experiment of multiplayer in the Mass Effect universe to try it out, but the people who are here for the story and gameplay can just ignore it and miss absolutely nothing. The fact that it's DLC also leads me to believe that it might not star Shepard at all and instead be a side mission, maybe in the First Contact War or something.
3)The fact that it will be DLC also means that, likely, it will be developed in the downtime between the game going gold and the actual release. Therefore, no time will be taken away from the single-player that is near and dear to our hearts. I know I could be totally wrong on that, as I have no idea what is going on in the secret Mass Effect Fun Lab, but neither does the person who says "It will take away time from the development! The game will only be 10 hours! OH NOES!" We have no idea if that's the case or not, so making predictions of doom is not helping anyone.
I totally understand that one might be uncomfortable about this- I'm kind of uneasy about the prospect of Mass Effect multiplayer myself. However, that does not mean we should run through the streets screaming about how EA is shooting down the skies and kicking our puppies. I am no less excited for ME3, even if this is true.