This feels like a ridiculous comparison. Free speech protects people from going to prison. Flexible OS options enable some personal choices with a product. Even if we take a much wider view of free speech (protection from corporate interference), this is still a massive stretch.
Free speech is enshrined in the constitution because, although dangerous, lawmakers generally believe that protecting it is critical to the long term success of the nation (and not every nation even agrees with this). I see no world where exec permissions on arbitrary directories on my phone is critical to the long term success of the nation.