Not much to say... Just why not?
All other colors have an achievement, why these ones can't?

Vortex doesn't have achievements either. Achievements are being worked on, see the last few pages of this thread for more information.

According to SkulFuk, the achievements overhaul is a long and tedious project. I'm interested in where the process is in this moment in time.

iirc, achievements aren't getting added until the system itself is fixed