Why can't I use BitMart in the USA?

I'm curious, why exactly can't I use BitMart in the USA? I've heard it's a popular exchange platform for trading cryptocurrencies, but it seems I'm restricted from accessing it here. Is there a specific regulation or law that prohibits US residents from using BitMart? Or is it a matter of compliance with certain standards that BitMart hasn't been able to meet? I'd appreciate it if you could clarify the reasons behind this restriction and whether there's any possibility of it being lifted in the future.