Shorting is easy and perfectly legal don’t know why the regulators don’t like it as it makes markets to remain healthy.
Just put cash up front and and use 1% of that money while the broker provides you with 99% of the balance money to go short, your funds are blocked until the transaction is settled, he helps you to make some money by your offering to the bids from his inventory, and then he offers the balance of his inventory to the rest of the bids.