They say as cryptocurrencies are highly volatile, one could go in great debt as reaching unprecedented heights is not promised to anyone.
Your statement here is true though. Bitconnect was outed as a ponzi, but it was regarded by many as a legitimate cryptocurrency prior to that. How many people lost their life savings in that? I'm not saying all cryptos are ponzis, of course, but even if you had put money in that, but did it
responsibly, then you shouldn't have any problems in the long run. I do believe most entities have hidden agendas in opposing crypto, but the warnings are likely there in part to encourage responsible behavior.
Either way, you shouldn't listen to anyone blindly. Governments have been known to be dishonest at times.