Believe me, if we really did practise censorship here, I'd love nothing than to permanently censor the exact type of crap that has been spewed forth left, right and centre in this thread. Here's a piece of advice: if you don't have access to 100% of the information on a topic, you should try asking about it nicely rather than opening with an ill-informed rant and embarrassing yourselves.
There's a few things I want to address here, the first of these being the reason the achievement was deleted. As has already been mentioned, friendly fire damage was originally not recorded and therefore the achievement was unobtainable. As was also mentioned, in the last two years it HAS been possible to obtain the achievement, but that's not to say that it hasn't been broken the entire time. The achievement description, as I'm sure you're all aware, states that the achievement is awarded for taking damage from teammates. Instead, for the last two years it's been awarded for dealing damage to teammates. In simple terms, it does the exact opposite of what it's meant to do, or in even simpler terms, it's broken.
The other reason given when the decision was made was that the achievement was "questionable from a game-design view", ie. it encouraged intentionally being hit by teammates if it had worked properly or, worse, intentionally shooting teammates to obtain the broken version. And if these reasons aren't good enough for you, here's a third one of my own: who the hell cares? Are those 50 achievement points really going to keep you up at night? Sure, it could've been removed sooner, but was never exactly viewed as a high priority. I can't believe people are actually willing to kick up a stink about losing one specific, low-tier achievement which they had to play like a njub to earn in the first place, if they went for it on purpose. And if you didn't chase it on purpose, you haven't been robbed of any of your hard work.
Finally, and more importantly, please refrain from re-posting deleted content. If something has been deleted, it was done for a reason. If you have an issue with the way something has been handled, feel free to take it up with me in private, but doing so in public in this manner won't be tolerated. Believe me, if I had been online at the time things wouldn't have been allowed to reach this ridiculous point. Now my options are limited and we're left with this mess.
So here's a little more "censorship" for you. Thread locked, and please try to refrain from creating another one.