that guy just thinks he knows everything well in fact he might just playing games. if he has plenty of believers and would dump btc whenever he badmouths then it will affect the price of btc.
it is unlikely that government can destroy btc. There's a lot of big time investors behind cryptocurrency and will not allow government just to ruin what they have started.
you need to transfer/deposit the tokens to specified exchanger, also make sure that you have enough eth balance before sending it or else it won,t transfer. Then, from the exchange you can do the trading buy and sell.