Why didn't your company disable it for just IE? It wasn't hard at the time to detect which browser people were using based on headers.
You could have checked to see which browsers turned it on by default and ignored them specifically. If IE went the route of trying to make IE's headers imitate Firefox's or something, fine, then disable it for IE and Firefox, but keep it on for Chrome.
But the idea that one browser misbehaving meant that suddenly no browsers could be trusted sounds to me like an excuse. Across the industry we build browser-specific behaviors for all kinds of things. What's so special about user tracking that nobody in the industry could do that?
Like if adtech companies weren't literally the best players at figuring out which browser a visitor uses.
Basically, Microsoft sacrificed consumer privacy as part of its petty feud with Google (and after their own attempts in ad tech went up in flames—taking a $6B write-down on their acquisition of AQuantive).