That toggle actually exist on iOS 14.4.2, and probably earlier versions (I could make a screenshot to demonstrate it). However, I think the ATT feature didn’t exist until 14.5 was released, but I’m not sure.It only explains it if you had manually turned it off before - e.g. if you were a beta user - since AFAIK this toggle didn't exist before 14.5. And most people, if they care enough about not being tracked that they looked to turn it off globally, they're not very likely to turn it back on again. So I can see how even a "competent" QA might have missed this.