The point being made above seems to be "Releasing the source for EE poisons dev efforts", because if I fork CE and add code that does something EE adds, GitLab might claim that I "stole" code from EE, or looked at EE and was tainted with knowledge from EE code.
Even if I hadn't copied code from EE, the claim could be made and would be destructive to the ability of community members to fork and improve the open source codebase