In the lore, the Quarians are driven from their homeworld, Rannoch, by the synthetic, hive mind collective known as the Geth. Abandoning their home planet, the Quarians are now nomadic, carrying millions on a flotilla consisting of thousands of ships. Their weak immune systems force them to wear environmental suits, thus shielding their face, and their appearance was a hot button issue. Eventually, her face is uncovered in the third game, but the revelation was met with a hostile response.
The anger originates from the scene below, but only if Tali is romanced.
And, frankly, the anger is justified. On the left is a stock photo found by some very astute fans, while on the right is a close-up of the photo.
Therefore, BioWare easily solved an issue fans have quarreled over for five years. Many have questioned BioWare's intentions, especially on the forums, as to whether this is the developer compensating for bad dialogue or some other terrible aspect (as perceived by fans).
Personally, I think BioWare was lackluster here. The mystery beckoned at least a little creativity, the amount of creativity it took to imagine the various races of the Mass Effect universe, and to not give the Quarians their due seems wrong. The studio didn't even remove the red nail polish! But I'm not a developer; maybe I'm just some overzealous, protective fan heavily invested in a series from the beginning. Who knows.
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