The copyright of the output of these tools is not yet determined, it's a risk.
The advice not to use the tools in a risky way not only directly mitigates the risk but like an "employees must wash hands" sign in a restaurant restroom, it can be seen as a reasonable step that transfers some of the liability to the staff member.
It's not a verdict on the output of the tools, it's a reflection of risk aversion in a monorepo company that is very protective of what is in the monorepo.