it’s allowed because it’s discussion group on the Internet.
In discussion groups, anything is permissible until content is removed by a moderator.
Content isn’t typically removed by moderators when they’re not looking. Often even if they are, it is not removed unless somebody complains. Even if somebody complains it is sometimes not removed because it is generating useful discussion, even if the impetus is questionable.
The fact that it’s here doesn’t necessarily mean it’s condoned by the community or the powers-that-be.
It’s like many laws that are on the books: You can get away with anything until the neighbors complain.
Paul isn’t complaining – he rather enjoys the attention and why not?