Inaccurate is one thing, dumb is another
Yes, we know biopics aren't supposed to be documentaries. They're not supposed to follow every fact closely as it exactly happened. Certain things are rearranged and/or embellished to make for a compelling story. But I'm sorry, even if you don't aren't an expert on the history, you can see a few giant glaring examples of creative license that simply insult the viewers intelligence. It's not enough to take liberties, you have to do it well.
For example:
Alan deciding what to do with the intelligence obtained? Which ship goes down which doesn't? Anyone with half a brain and a bit of familiarity with how governments work knows that is ridiculous. He's the code-breaker. He's not the commanding general, the head of MI6, or the Prime Minister. You break the code and you more or less move on to the next one.
Speaking of MI6, Alan telling the head of MI6 how to use the information so that the Germans don't catch on and realize that they broke ENIGMA? I'm sorry but you're talking to the most powerful spy agency on the planet. It's their goddamn job.
And by the way, the genius moment when Alan realizes how to break the code. First, it was a carbon copy of a scene in a much better film starring Russell Crowe. Second, the moment he said to look for common words I just thought to myself, "You haven't been doing it this entire time???" The amazing genius hadn't thought of this up until this moment? Again, insulting the intelligence of the viewer. (Turns out they were already doing this for a 100 years, there was no such moment of epiphany)
And finally, the first scene with Keira Knightley. I get people were much more sexist back then but a little subtlety please? One doesn't need a degree in history to know that scene never occurred. It's so obviously heavy-handed and fabricated.
So I guess my point is, it's not the inaccuracies that matter as much as the dumb way the writers went about them.