>>5 >>2 It'd likely a group of Americas trying to Americanize a word that is from another culture and language to mean something else which they have no right to, the only people who can change the meaning of the word is if you are 100% Japanese and are living in Japan anyone else can GTFA.
If you went to Japan and said out loudly "I am an otaku" people would likely look at you strangely and try and stay far away from you.
Just because in some Anime the word otaku is used a lot it is meant to be an insult to whom ever that it is aimed at, not like saying "oh you such a geek or nerd".