No, it's just not speaking idiomatically. The term "open source", with or without caps, has a commonly understood meeting that's widely used. Whatever the individual words mean in the dictionary, together they have a well defined meaning. Applying it to other situations that contradict that meaning just adds confusion.

As an example, you could describe a spinning disk hard drive as "RAM" because it's a memory device you can randomly access. That would meet the dictionary definitions of "random", "access", and "memory". And yet, everyone would be annoyed with you for doing so. "I have 16TB of RAM in my computer!" "No you don't, Kebab. Stop saying that!"