Cursor might have framed it that way at the time, but 4 months prior Anthropic cut OpenAIs access under the same clause in the ToS: https://www.wired.com/story/anthropic-revokes-openais-access...

And a month before the OpenAI block, they blocked Windsurf for the same reason: https://www.forbes.com/sites/johanmoreno/2025/06/05/anthropi...

So its pretty clear the TOS had this clause prior to Jan 2026.