In the past, Robinhood has removed cryptocurrencies from trading after they were alleged to be securities by the SEC, such as Solana (SOL), Cardano (ADA), and Polygon (MATIC) in the wake of the lawsuits against Binance and Coinbase. However, given the SEC's stance that most cryptocurrencies are securities, it seems likely that the SEC believes one or more of the 14 non-bitcoin cryptocurrencies Robinhood offers may also be a security.
Robinhood's Chief Legal Officer issued a statement that "We firmly believe that the assets listed on our platform are not securities and we look forward to engaging with the SEC to make clear just how weak any case against Robinhood Crypto would be."