No one was forced to use IE, but many people had the decision made for them. Sometimes it was because it shipped as the default on the dominant operating system. (I suspect people forget how dominant Windows was. While Windows remains the dominant operating system on desktop computers to this day, their share wasn't diluted by platforms like Android and iOS.) Other times it was because sites designed exclusively for IE were visibly broken in other browsers. (I suspect part of the reason why I am not bothered by incompatibilities with Firefox to this day is because the incompatibilities are minor compared to those we faced in the past.)
I do agree with your sentiment about conspiracy boasting, though from a different perspective. Their actions represent a group of people in a position of power making a decision for other people, even if it wasn't an officially sanctioned decision. (Though I have no doubt that many people cheered for their actions.)
Ehh, plenty of corporate IT decided to force employees to use IE. That's actually my main interaction with programming for it, clients that HAD to use IE due to corporate policy.
And I don't think the conspiracy in this article is something to boast about. It's literally using dishonesty with the higher-ups (no matter how much you might hate them) as a way to make your own job easier.
Plus, stuff like this is why we ended up in a Chrome monopoly, to the point that even Edge finally got Chromified.