Some people doing join requests are more lenient than others, is what it usually comes down to. (: And I'm sure some are mistakes as well.
However, those in question, such as Koz Ofyurdeth, are not actually in the filter as banned names, and therefore still require manual approval.
I believe the suggestion here is to add canon names into the coded filter so they would not even be able to get to the next step of the approval process without entering a different name.
Still an issue as, like I mentioned, basically all canon names would need to be added if any are.