That is the publicly communicated reason for the ban. They could be sued by law-abiding ICO's as well. No one is guilty until proven otherwise. The presumption of innocence does apply for ICO's too. So whole argumentation smells like discrimination. You could also argue that the ban and an upcoming issueing of an cryptocurreny , is a breach of competetion law and an abuse of marketpower. As I wrote, it's worth an own article.