This appeal falls flat when you get to the parts about their homeserver requiring some form of age verification:
> From our perspective, the matrix.org homeserver instance has never been a service aimed at children, which our terms of use reflect by making it clear that users need to be at least 18 years old to use the server. However, the various age-verification laws require stricter forms of age verification measures than a self-declaration. Our Safety team and DPO are evaluating options that preserve your privacy while satisfying the age verification requirements in the jurisdictions where we have users.
Which is actually more strict than Discord's upcoming policy which allows accounts to operate for free without any verification, with some limitations around adult-oriented servers and content.
There has been a lot of FUD about the Discord age verification, so a refresher: The upcoming changes do not actually require you to verify anything to use Discord. It just leaves the account in teen mode by default. This means the account can't join age-restricted channels, can't unblur images marked as sensitive, and incoming message requests from unknown users will go to a second inbox with a warning by default.
You can, of course, run your own Matrix server. Having been there before I would suggest reading up on some typical experiences in running one of these servers. Unless you have someone willing to spend a lot of time running the server and playing IT person for people using it, it can be a real headache. They also note that running a server doesn't actually get around any age requirements:
> Practically speaking, that means that people and organisations running a Matrix server with open registration must verify the ages of users in countries which require it.