This is cope and propaganda to discourage people from developing their own brand. Better for the corporation if the workers have no support structure or reputation that might lead them to quit
"Developing your own brand" is not a scalable solution. There's only ever going to be a few thousand developers who are well enough known to be called a brand.
"Personally, I like to publish nothing and collaborate on nothing outside of work, because I like corpobux more than anything else. I'm too stupid and slow to conceivably make anything worth writing about"