He wasn't meaning to be offensive, hostile or aggressive, he assured the imposing panel giving evidence to the Parliament's education committee meeting last week. He was just keen - some might say doggedly determined - to find out the answer to one itsy, bitsy, teeny, weeny question: what will A Curriculum for Excellence look like?
Mr Macintosh was only asking because he thought parents might be interested to know. (What about the teachers, we thought: they might also appreciate a hint. But he got round to teachers later.)
Scottish Government official Alison Coull explained she was "not in a position to tell parents what it will look like". That was an unsettling revelation, given Ms Coull is deputy director of the curriculum division.
She thought the biggest hurdle on the road to the new curriculum wasn't the "lack of clarity" with which Mr Macintosh seemed so concerned, but "cultural change". In education, she explained, people were used to a "prescriptive approach" and, for some, the "new freedom" was "quite scary".
Naturally the valiant Sir Ken wasn't scared, but neither was he entirely convinced. "Where are we heading?" he persisted. "We can't just be heading into the unknown."
"Ministers are considering the possibilities," Ms Coull said gravely.
But Sir Ken would not be cowed. Will a maths teacher still be a maths teacher? Or will they be teachers first and specialists second? Will subjects be protected? Will pupils still make subject choices in S2?
By this time, ministers had got round to "actively considering" these questions, Ms Coull said.
Chris McIlroy of HMIE tried to offer some clarity: published advice, he said, makes it clear that subjects are a component of A Curriculum for Excellence.
This seemed just the kind of response Sir Ken found a bit vague.