I remember hearing that particular brand of philosophy about raising children so they wouldn't be bored in Kindergarten back when I was in college a couple of decades ago. It comes from ignorance about the subject and from an institutionalized mindset of making things easy on the teacher because none of the kids are a challenge to keep engaged.
It probably won't be the last time you hear something that rubs completely against what you know to be best for your child, but since this woman is in a place of authority over other children - and if you are willing to risk losing the use of that facility if they get mad and ban you - you could definitely escalate on this with the director. She overstepped.
