It is possible that because of the nature of counterintelligence investigations, the individual companies agreed to gag orders while law enforcement does its work.
Also, these companies want to continue to do business in China, and likely do not want to be on the record accusing the government of a massive criminal conspiracy.
Also, these companies want to continue to do business in China, and likely do not want to be on the record accusing the government of a massive criminal conspiracy.