> Because they like community contributions to their stuff, so "open source" it for that, but don't want their competitors benefiting from the initial work they did. Which I understand.

The distinction between competitors and community contributions is false. Why should the publishers be entitled to exclusive monetization of the contributions of their community, and why should their community be denied the right to monetize a product they contributed to? The ability to share the wealth is why the open source movement works.

This approach stems from a position wherein the publishers view themselves as separate and privileged from their community, which is valid if you are the only entity investing in the software, but unjust if the community is an active participant in the software's development.

The mainstream view on OSS is often good for the original publisher, in that an organization which monetizes their software then has access to more resources with which to contribute back to the software -- particularly in the presence of a copyleft license to enforce this behavior. The original publisher is then able to benefit from a larger and more consistent workforce developing the project with them.