I think its understandable that some would want longer hair styles, sure. However, why is it so strange that some people prefer short hair or updos on characters that are engaging in battle on a regular basis? It would be great if the pc had the ability to let their hair down during down time, but I don't see them putting in extra effort for it. You can use the argument of "fantasy game" pretty much anywhere. But truth is, there are just certain things that suspend belief for people, even in a game about space magic and mind-melding alien chicks. It may not be long hair for you, it may be something else. But come on, I can't be the only one who raised an eyebrow at Ashley's ME3 hairstyle, especially since she had it pulled back the last two games.
Besides, I think it's less "no one should be allowed to play a character with long hair", and more of hoping they put in the time for decent looking short styles and updos first.