It's exactly what you've said. I'm speaking about Anthropic though, I have no idea whether OpenAI does it.

> Anthropic agrees that Customer (a) retains all rights to its Inputs, and (b) owns its Outputs. Anthropic disclaims any rights it receives to the Customer Content under these Terms. Subject to Customer’s compliance with these Terms, Anthropic hereby assigns to Customer its right, title and interest (if any) in and to Outputs. Anthropic may not train models on Customer Content from Services. “Inputs” means submissions to the Services by Customer or its Users and “Outputs” means responses generated by the Services to Inputs (Inputs and Outputs together are “Customer Content”).

This is the only commercial ToS clause about how they handle your data for subscription users. They only promise not to train the model on your exact input and exact output. There's nothing about not washing your data - the "clean-room" approach, which is obviously easily automatable by a company that specializes in automation. That is not training a model on your data, it is using a model to create derivatives of your data, then training it on "their" derivatives.

People really needs to apply pressure and start demanding answers from these companies regarding this - because it is a huge problem. Historically, the amount of labor required to do something like this would make it entirely unfeasible, so this is all new territory. The existing laws and the requirements around clarity surrounding these conditions do not reflect the technology progress.