This just seems wrong to me, maybe i'm misunderstanding it.
You are. Open Source is in itself a protected term. A project under Open Source license is using a license that has been approved by the OSI – and all those licenses imply, by definition, that the licensed product is free (as in free beer)1). There is no discussion about that.
CKEditor is an instance of double licensing. But their commercial license does not negate the fact that it’s also OSS, which makes it free for you, if you can abide by the remaining terms of that license. If you can’t, your only choice is to pick the non-free commercial usage license.
As a developer, if you contribute to an Open Source project, you are contributing to a free project. Sure, the maintainer may still make money from it, but so what? It’s still free to use and modify for everybody who wants to. As a “service in return”, if you will, the maintainer makes sure that updates are incorporated into the code, pushed to distributors and published.
1) First point of the Open Source Definition