Tavis Ormandy started tweeting at AVG about this subject several months ago.
And it's been pointed out that they aren't able to remove the extension from users' machines due to how it bypasses the Chrome security system. So their best bet was to ask AVG to do the right thing. AVG won't or can't.
So, what can Google do? Just silently accept it? The 90-day policy is worthless in this case.