The answer to the question is really simple: if you are not licensed by the US government, they don't want you to operate anything that can transmit money around, since crypto currency has been generally accepted as money, not like the old days when they saw it as something that wouldn't succeed.
The US government wants to be in control of whatever service their citizens are making use of, which can allow them to send or receive payment. Any service that can be proven to a money transmitter is either getting a corporation license or the three-letter US agency will come right after you.
Now I think they have succeeded in getting most of the centralised exchanges under their control and watch, so what's left next is self-custodial services. Don't be surprised when they go after Metamask and other web wallets that US citizens are allowed to make use of, as the SEC has already declared Metamask to be an unlicensed broker-dealer, so the next step is to get it shut down whenever they want.
The SEC, FBI, and other government agencies that are responsible for the regulation and attack on crypto firms are all doing this because they feel crypto currency and other services that offer privacy are obstructing them from having full monetarily control over their citizens finances. Like I said before, these people just make the rules to suit them and come after anything that poses a threat to them.
