first of all, itch is in US and does not give much for any perceived rights you seem to think you have. The tos quite clearly states which law is applicable. And that ain't European law. This is their site, they can remove you for "If you misbehave we may terminate your account."
And second and most important, you mistunderstand something essential. Your losing your account has nothing to to with itch terminating your account. But everything with you not responding to critical mails that might save your account, like password recovery. Read againt what leafo wrote. You might lose ACCESS to your account, not that the account would be terminated or banned. How would itch even know that you blocked their mails in the first place?!
Anyways, leafo does skirt around/ignore the real problem, namely that there is a mechanism for unsolicited mails. No consent is given when purchasing somehting that you end up on a mailing list. Internet 101 says, this is bad practice. They do not even automatically make you follow the publisher, they only recommend this. Why not the same for the mailing lists?!