I think it's largely in response to the level of interest it generated on the board, and to be honest it was a valid way to look at spells without an FAQ.
The question wasn't ever really about if you met the pre-reqs when you had a higher skill, it's a spring board to attack 3rd lvl counting as 2nd or greater.
It honestly did need an answer, not because the answer wasn't obvious, but so that they could make a distinction between spells vs skills linear progression.