It's simply a matter of perspective.
http://img150.imageshack.us/img150/5923/colorsli1.png
Some would say the middle color is blue, some would say it is purple, however it is an even mix of both. If you dont believe this works as I have used it, take the RGB of red (255,0,0) and yellow(255,255,0) and average it out (255,127,0) and youll get a nice orange.
Perhaps the bright yellow on the shoulders is what makes it to appear more blue seeing as yellow is diametrically opposed to purple? I personally think it is a mix of both. Neither close enough to blue to call "blue" nor close enough to purplr to call "purple"
Edit: I know the middle color is not the same color as adaberk. Rather I am trying to point out that the split in people saying "its blue" and "its purple" comes fromt he fact that really, it is a mixture. The picture was an example, as some people would label it as "clearly blue" or "clearly purple" when it fact it is an even mixture of both.