It is Microsoft's problem that they have IE default to rely on what nearly everyone agrees is a crap solution
Do they? Then what's the point in the standardisation process? The whole point is that everyone agreed on a solution in P3P. Maybe it wasn't ideal, but it was the standard. So, faithfully, MS implemented it.
So, MS is to blame when they go alone and make their own standards, but they are now also to blame when they follow the standardisation process to the letter and other people don't?
You don't get a free pass because you're following a W3C standard. The way P3P is implemented in IE made web developers lives harder in exchange for virtually no additional privacy protections to users.
The point of the standards process is so that we don't have multiple competing/incompatible/ambiguous header-based privacy policies. But that's not the problem here. There aren't any notable competing privacy headers because the whole approach is flawed.
Are you going to say the same thing about the FileSystem API, Dart, and NaCl? Google is probably the worst browser vendor when it comes to having competing implementations of their proprietary features.
There was a standardization process, then the committee in charge of it gave up on it because it wasn't going anywhere except IE. See the home page of the working group (http://www.w3.org/P3P/). It's time IE woke up to that reality.
Do they? Then what's the point in the standardisation process? The whole point is that everyone agreed on a solution in P3P. Maybe it wasn't ideal, but it was the standard. So, faithfully, MS implemented it.
So, MS is to blame when they go alone and make their own standards, but they are now also to blame when they follow the standardisation process to the letter and other people don't?