Hello,

on our server, the few PuG raids that happen, often involve ninja looting. Or at least, it often happens someone gets accused of it.
Now, the forum policy says we can't name and shame.

Would it be allowed though, to make a topic in the realm forum, linking to an external site, where ninja looters (with proof) are listed?

No. In essence it would be just the same as posting the names on these forums.