Everything Robinhood is doing is wrong, but the reason they are closing these positions is they are over leveraged and Robinhood too is a afraid they will never recoup the money if the investor goes millions in debt.
Af far as I know they haven’t sold anyones actual shares, just closed over leveraged positions. Still wring to do it but being able to levarage investments goes in the same book as a short in my opinion, though it doesn’t have a negative side to the company’s ownership like a short might