strange request from the advocacy site

Hi everybody

Yesterday I got a mail from the advocacy site.
A person subscribed to a PostgreSQL mailinglist and now is surprised
that he found his email adress at google.

He is blaming the PostgreSQL-team for making his email public saying
that this is not a professional behaviour and that he is disappointed.

He requests to cancel his email-adress from the archivess immediately
saying that he never gave the right to the PG-team to make his adress
public.

I answered him that he himself made his adress public by writing in a
public mailinglist and he should contact the listowner for any
questions or problems.

How to avoid such annoying discussions?
Are there any legal statements to point those people to?

Greetings
Conni