Let us analyse the logic table:
Late NotLate
Did A B
Did not C D
A:
He came home late yesterday
B:
He came home, but was not late.
He did not come home late.
C:
He did not come home, but he was late.
D:
He did not come home, therefore he could not even be late.
Therefore,
He did come home late yesterday
is case A.
However,
He did not come home late yesterday
is not case C, but a combination of possibility of B, C or D:
- D: He did not come home late yesterday, because he never did come home yesterday.
- B: He did not come home late yesterday, but he did come home. He was early.
- C: He came home late but not yesterday. He did not come home yesterday. He came home this morning.
That is, in a two-bit binary event,
{Not A} does not equal {C}
but
{Not A} equals {B | C | D}
Normally,
He did {perform}
is an affirmative form of
He {performed}.
Child 1: Mom, I did not eat ice cream as you told me not to.
Child 2: Mom, he did ice cream.
Child 1: No, I did not.
Child 2: Mom, he did. He ate ice cream.
Placing the word did does not modify the sentence logic but its emphasis. And therefore, your conjecture on the sentence having gone thro a series of typographical inaccuracies need not be made, because people do use did in such manner to emphasize. It is not sloppy, but a deliberate emphasis. You are seldom sloppy when you deliberately endeavour.