My understanding is that Maria Montessori never copyrighted her name or method, so it's actually a free-for-all where anyone can call their toys "Montessori", like STEM, not some central organization selling merch.
This goes for the schools too! There are "accredited Montessori schools", but any school can call itself Montessori with no penalty.
Yeah, there are a bunch of toys on Amazon with the "Montessori" label that have nothing to do with the official/traditional Montessori materials (which are specifically not called toys).
It's become a marketing term for any toy that's educational and made of wood.
This goes for the schools too! There are "accredited Montessori schools", but any school can call itself Montessori with no penalty.