If it prohibits its people from earning income from buying and selling cryptocurrencies, it means that all types of online gambling must be stopped as well.
Cryptocurrency wasnt really created for the sole purpose of making income or would generate profits into those people who do tend to engage with it but instead it was created solely for the purpose of making p2p transactions and earning income is just a bonus or one of its benefits since its been common
adopted widely and if a certain government do really make out some decision that its citizens shouldnt really make out some involvement then its just understandable that they would really be following those orders but due to anonymity of crypto then for sure there are some who sure would really be playing with fire.