>How far is this?
If I am understanding your question, they went so far as to sue their employees.
You are getting downvoted because, I guess, people didn't read who the defendents who are getting sued, and that it literally starts with sueing two employees:
CHANG LIU, TANG YEW TAN, OPENAI FOUNDATION f/k/a OPENAI, INC., OPENAI GROUP PBC, and IO PRODUCTS, LLC f/k/a IO PRODUCTS, INC.,
Is this uncommon when it comes to corporations? Sue the people who (allegedly) did the thing?