they operate binance.us and to fully say cz has zero to do with binance.us was likely impossible. thus the us went after them.
They started binance.us as a separate thing to avoid problems such as this. Apparently that didn't work as well as they hoped.
I always wonder why they would operate binance.us as it would tie them into usa taw rules.
Because US market is always a good revenue from a business perspective. The population is high and so is the number of potential customers.