I think they don't learn more about cryptocurrency so they can easily to say like that. If they can spend their time to learn about cryptocurrency, they will know that the cryptocurrency gives them a way to make unlimited income and they can find that they can make money in different ways. The cryptocurrency traders are not scammers, but people in out there is trying to get other people money, and they will use many ways to reach their goals, and they will scam the people.
So before you get involved in the cryptocurrency, make sure you learn from many sources, and if somehow you decide to invest in cryptocurrency, you don't have to use all of your money and only use the money you can afford.