how can this line can't be true with new account ?

@Supertoff There was a line 28 in the version of the filter used at the time those accounts have been created, see the link in the description I wrote above. See also the email on which you are in CC ;)

Some of these can be managed by metawiki's title blacklist. We already do that for numbers of prominent users, and would do that in this situation where duplicity is being attempted. Happy for a strings of regex to be provided to the talk page to achieve this, also noting that we have the antispoof ability there too.

I think that doing this globally is quite important as we don't want prominent users being mimicked at other wikis either.

There is also https://meta.wikimedia.org/wiki/Special:AbuseFilter/251 that someone has created for monitoring something similar

Thanks @Billinghurst, I will keep in mind this possibility.