Tornado cash, taken down by the US government, had a victory in the US Court of Appeals:

Sanctions were unlawful, according to the court.

Taken down by the US government?

According to the Wikipedia, Tornado Cash is an open source, non-custodial, fully decentralized cryptocurrency tumbler that runs on Ethereum Virtual Machine-compatible networks.

But if it is really fully decentralised, then how the US government could take it down?