Ich hab mal den Support von Poloniex angeschrieben und nachfolgende Antwort bekommen. Scheinbar können wir es doch weiter nutzen.

The User Agreement is not “addressed” to users in China, Pakistan, Germany and Vietnam because local laws appear to make certain uses of cryptocurrency unlawful or regulated in those jurisdictions. However, if users in those countries choose to use Poloniex, we will not prevent them from doing so. Such users are protected by, and subject to, all of the provisions of the Poloniex User Agreement.

Your account will remain open and fully functional after this update. Your funds will remain protected, so there is no need to move them at this time.

If you have any further questions about how this change affects you, please let us know and we will be happy to help.

Best,
Poloniex Support Team