It's the federal mixing rule (along with other things), which it seems they are refusing to fight in court (it hasn't been finalized yet, but it will be soon).
https://www.federalregister.gov/documents/2023/10/23/2023-23449/proposal-of-special-measure-regarding-convertible-virtual-currency-mixing-as-a-class-of-transactions
(Comment period on this ends in early 2024)
There is also an extremely strong anti-bitcoin (and anti-any-sort-of-digital-innovation) climate as a result of what is happening in the federal government in the United States right now. See recent SEC prosecutions, etc. This doesn't make it impossible for people to operate in the USA, but it does make it extraordinarily onerous and it does make it increasingly necessary for individuals and organizations to plan legal battles simply to continue to use decentralized, distributed, dis-intermediated systems in the United States.
Now, Wallet of Satoshi could ally with various other groups including pro-bitcoin groups that have had success at defending both industry groups and individuals from legal onslaughts.
Instead, Wallet of Satoshi (nprofile…yv3a) is retreating with its tail between its legs.
Let me add that an organization that absconds from a state, I can understand. For example, Kraken removed itself from New York after New York decided to implement the NY bitlicense, which meant that individuals in New York would not be able to be served by Kraken, but that corporations that had been formed out of NY or individuals residing outside of NY would be able to be served by Kraken. At that time, Kraken had released a blog post which described in detail exactly why they were leaving New York and explicitly described Kraken's total opposition to the NY bitlicense. As time went on it was apparent that it was still possible that NY residents could be part of a corporation that was incorporated outside of NY and thus could be part of a business / corporate account on Kraken along with other corporate officers, although today a person residing in NY cannot have an account as an individual on Kraken. Since many exchanges withdrew from NY when NY implemented the bitlicense, I wonder how many exchanges will withdraw from serving clients in California when California's bitlicense (AB 39, now law) goes into effect in around a year's time. I hope many of them will, but there would be an enormous impact on the market if they do so and I don't think all of them would be willing to give up the money, they'd rather cave to California's demands.
So as I said, I think that it's understandable if an exchange (or a software business, or any kind of bitcoin oriented organization) decides it might not want to serve a particular state (because of licensing requirements they don't agree with, so long as THEY MAKE IT CLEAR THAT THAT'S THE REASON FOR WITHDRAWAL from that state). However, withdrawing from an entire COUNTRY seems ridiculous to me unless you are acknowledging that you simply aren't capable of serving the people in that country. Wallet of Satoshi's statement that they "will not serve" people in the USA is not acknowledging Wallet of Satoshi's own inability to figure out a way to serve people in the USA - rather, it's just a cop-out by saying they "will not serve" people in the USA.
Sound negative? Sure, but I'm just being honest.
Do better, Wallet of Satoshi.