How many times have you memorized the words to a song, only to discover later that you never really knew the words at all? That happens to me even after I know the real words.
And that happens in writing nearly every time someone writes, which is why editors have to be ever vigilant and why editing is as important as ever.
In this case, I suppose it’s possible that the purposes we describe were intensive (a strength or intensity imposed from outside, according to American Heritage).
That’s not likely, though.
What we were after was for all intents and purposes, meaning for all practical purposes.
Oops. Now you know.
A related aside: Intense and intensive have slightly different meanings. For an insightful explanation of the difference between them, see American Heritage’s usage note under intense.