I guess discourse in software development is very normal (and needed) and in the case of free software, it is generally held publicly. Well they still give away their code for free. Everyone is allowed to do the same thing the blender foundation does - aquire resources to fund blender’s development and sharing the product with everyone who wants to use it.
edit: reading the thread on blenderartists… that developer seems to be a bit of a drama queen… I can’t comment on the technical things as I know close to nothing about it, but him being rude like that is not good for any working environment.