This was a well thought out, lengthy contract written by a legal team. If it’s true that “everyone” who works there signed it then it’s not the result of a “recent” problem. There were noncompetition and other clauses but this was a separate section, and it wasn’t a no moonlighting clause.
DC did attempt to make alterations directly on the contract (as other family members in other industries have done) but the employer claimed to not understand the contract and wouldn’t even discuss it. The suddenness and intensity of the pressure started from the instant the employer learned DC actually consulted a lawyer. It makes me wonder if some people don’t know enough to consult one.