Oh, the drama.
If you ignore someone you should ignore them. If they harrass you, report them, again and again, silently. They will lose their account. And if they come back, that one will be gone again. I saw it happen several times. Do not try to deal with such people yourself. They draw you down to their level and beat you with experience, as the saying goes ;-)
But I agree that itch is acting problematic, because either they allow someone stating they are in violation of the tos to post in the community or they allow someone impersonating a kid to post in the community, wich is another violation.
So no matter how you spin it, someone claiming to be 11 should not continue to have an account here, especially when misbehaving. At least no posting and publishing privileges.
The relevant portion is this
https://itch.io/docs/legal/terms#3-acceptable-use
- Bullying, intimidating, harassing, defaming, threatening others, or violating the legal rights (such as rights of privacy and publicity) of others;
- Creating a false identity for the purpose or effect of misleading others;
And of course
Users affirm that they are over the age of 13, as the Service is not intended for children under 13.
And I am not sure, what law itch would be violating. It is their show, it does not matter much, if they "violate" their own tos. It is still their show. Is there a law that makes a tos a law?! Even if, where in the tos does it state, that itch has to enforce their restrictions? It is a contract between you and itch and not between you and other users. Also note, that it is written "intended" and not "forbidden". And furthermore this is tos to use itch, like publishing. Rules in community are on top, but basically, it is, be nice to each other. So use that report button, if someone violates that, and do not zeal out yourself. It makes one look bad and achives not the desired effect.
I wish all parties involved some calm and quiet. This is the internet, but you are all dealing with real people. Be nice. Think about what your mother would say to you, if she knew what you are doing, if in doubt.