The only problem was that AV vendors should have the same access as Microsoft's AV tools. If Microsoft had said, "fine, everybody, including us, only has access from outside the Kernel," that would have been fine and is what they are actually now doing.
Which raises the question - barring EU legislation, what exactly is the issue with Microsoft reserving kernel access for themselves while blocking every other third party vendor from being able to access it? Some misguided notion of “fairness”?