The supposed Ryan's message does not say anything about stock shorting and it can have many different meanings. Even the receipt didn't understand it that way as shown in his reply. The receipt is the one who added the VFIN comment in a tweet later then some started building up on that. Probably he found VFIN jumped in and price dropped so he assumed that's the meaning of the message he didn't understand at first. Try to read the original message again for what it actually says (or doesn't say) and find if it means shorting the stock.