[Wikimedia-l] Is the capability to delete usernames compatible with the CCBYSA license?

[Strainu]

Hi,

Someone brought up an interesting issue: is it moral for the vandals
to be credited as contributors to articles (especially when exporting
the article as pdf)? After experimenting a little, it turns out that
deleting the usernames from the history removes them from the
contributor list.

While morality is a subjective matter, a more interesting question is:
is this behavior compatible with the CCBYSA license? Say we have
version A of a text, vandalised in version B and reverted in revision
C. Then version C is a work derived from version B, shouldn't it
credit the full author list of version B?

Going further, say that someone with an offensive username (or even
just an username unaccepted on wikipedia, such as a company name)
actually makes a valid edit, which is not reverted, but the name is
removed from the history. Is it fine to ignore the license just
because we find some usernames offensive? Shouldn't we instead credit
the user *at least* with a pseudonym?

Thanks,
   Strainu