Why can't I use MEXC in the USA?

I'm curious to understand why MEXC, a popular cryptocurrency exchange, is not available for use in the United States. Is there a specific regulation or law that prohibits its operation in the country? Are there any security concerns or risks associated with using MEXC that the US authorities are trying to mitigate? Additionally, are there any alternative cryptocurrency exchanges that US residents can use safely and securely? I would appreciate if you could elaborate on the reasons behind MEXC's unavailability in the USA and provide some guidance on alternative options.