So, you were only looking to play the game for a short period of time ?
I can understand why this system is frustrating for you then.
For the player looking at the game as an evergoing long term adventure, like EvE and other persistent mmos, their is absolutely no problem with the DAC/PLEX system running as an alternative to the monthly subscription.
As a player not infusing $$$ into the game , you would still be able to earn money otherwise using the game mechanics.
As long as it is not possible to progress your skills faster using money, DU can't be "pay-to-win".