Web of debt

Has anyone read web of debt ,Sheared by the shorts . I apologize I am not sure how to post a link but if you google it you will find it. It says that the majority of accounts held with brokeres are actual margin accounts that the clients don't utilize or even know they have the capacity to. This adds to shares being lent to shorters and advises all to contact brokers to change accounts. Interesting if it's true