Results on a standardized test are one thing: improvement observed by parents in better reading abilities are another, different, thing. Not all students results were augmented by teachers or principals; not all parents commented on their child's progress.
Cheating on test results by teachers does not mean in any way that all students did not learn what they were expected to learn. Some may have learned more and not all tests were fudged.
While it is clear that teachers should not have changed answers and scores, it is not necessarily true that every student was in some way cheated.
I suggest that teachers were not "teaching kids to be dishonest", as it was obviously not a part of the plan to tell students that cheating had been done on their behalf. To be taught dishonesty, you have to be aware that it occurred.