Steam has no reason to accommodate those who do this (unlike EU actions within the EU).
Now this all depends doesn't it. Are you saying that when the publisher obviously doesn't care, that Valve are still allowed to dictate whether you can have access to that publisher's content?
While I can't comment on the specifics of this case, I can comment on Mafia 2 in which the content available from locally sold retail versions (and Steam sold versions) is different to that of import versions. For one thing, the local version is in Japanese only. 2K, themselves, suggested that those of us who wanted to play in English, import the game from the US. And even went as far as linking to various sources to do so.
It was then found that Valve were locking out activation of those import copies. Once 2K were made aware of this, they instructed Valve to remove the IP blocks. Further, they now sell the uncut English language version directly in Japan via Amazon JP's download service.
The same happened with DNF. Only in that case, 2K were selling it to us via non-Steam sources. Again, once informed it was unplayable, they not only instructed Valve to remove the IP block, but to also sell the game to us.
So my point is that 2K have shown that they don't have any problem with people playing specific versions of their games in specific regions. So why are Valve now dictating which regions can access specific content published by 2K (and any other third party publisher?)
Do you not see an issue with allowing Valve to do that (against publisher wishes)?