We had DS in a Montessori school for less than 2 weeks before it was an obviously wrong, wrong, wrong fit. For DS - they offered the antithesis of creativity because all materials were to be used "this way ONLY."
Toxic words for DS, and really nothing more than a challenge. To be fair to DS - in our house we often play the "how many ways can you use a brick (or other mundane thing)" game. All sorts of things get used in unintended way. Witness the silver cheese knife and combination lock being used as kitchen radio antenna; old play yard fencing directionally propped to rebound basketballs; hotwheel track made of traffic cones, tomato cages, toy trucks, planks of wood and styrofoam packaging blocks; and the myriad things (including my glasses) held together with twist ties, rubber bands, twine or the blessed duct tape.
I think of Montessori as encouraging "bridled creativity." It puts me in mind of the Season 1 Simpsons episode where Lisa's band director scolded her for an "outburst of unbridled creativity." Here is a link to a thought-provoking review of that episode.
http://www.theandrewblog.net/2016/01/20/simpsons-moaning-lisa/ (FYI - I don't know who the blog author is. I just like the way he writes.) It's a lovely episode, highly relevant to the struggles our kids go through with respect to creativity and thinking differently.
Short answer - that teacher is practicing bridled creativity. Ignore.
