Legendary backpiece PVP

So not sure how to put this but i will try.

Recently i began to do legendary itens after been playing for a while. Today i was curious to see what i need for the legendary backpiece from pvp.

And as stupid this may sound most of the achievments ( Path of ascension ) "i have done them all "but it didnt count because i didnt know i had to finish path 1 to unlock path 2, which i am ok with.But if its supposed to be like that, why the hell i can buy pvp wings and other itens that counts towards achievments points from the Path of Ascension Part 2-3-4. If that is the case, why all rank points, kills, ranked wins did not count towards Part 2 -3-4. Just because i had to fuse something in the mystic forge ?! to unlock the next path??

Im just confused. Dont understand the logic behind it.I know there´s no fix whatsoever and im the one to blame since i should pay attention.

But well i felt like ranting.