To my knowledge you can only go to the EHCR once you have depleted all your national legal options, which can take about a decade here in Europe. Given that the Italian government is now run by actual neofascists, who also control most of european institutions (hand in hand with the classic "liberals"), i don't think a small non-profit anarchist host has much chance to win in court.
Even if they do win in court, it will be far too late for their thousands of @autistici.org emails. And even with a court victory, there's no guarantee technical intermediaries may ignore US sanctions (despite what EU ruling says). The only real solution is to get rid of US hegemony over the DNS, the banking system, the global military balance, etc.