Interesting question. I think you would have to contact support about it. (It would be kind of awkward if someone gained access to your account [former partner, cheeky “friend”, angry sibling, …] and removed your entire library with just a few clicks, so they would probably like to stay on the safe side.)

Just so you don’t get your hopes up: My experience with trying to remove games from my library on another site was that they straight up wouldn’t do it - even for free games and demos. On the other hand that site was heavily numbers driven (or at least they tried to be), while itch seems to be pretty relaxed about that. So there’s always hope.

And now for something completely different: To the best of my knowledge, the Chinese government is close with yahoo.com. Like really close. On the topic of access to your accounts: Consider who could be archiving your emails. (Of course if you’re not bothered, you wouldn’t have to take any actions in that regard.)