… software when necessary to use a tool (e.g. CNC) makes more sense to be as open to user modifications as possible …
Absolutely; it does make more sense. As such, it’s clear why certain forces maintain a vested interest in nipping it in the bud. Even so, such forces don’t ultimately stand a chance. The only real hurdle for us, are those cases where specific machines are out of reach for non-professionals; ie MRIs, huge milling machines, megawatt particle accelerators etc.