I don't understand the point of this post. It's full of fluff. Is he arguing that people should open source the add-ons they create for Blender?
"Blender add-ons (Python scripts using the Blender API) have to be GPL license compatible. You pay for the service to download it, not for the software. Never feel bad about harming any GPL developer by sharing her/his code. Sharing is an act of love!"