Why are so many crypto exchanges banned in the USA?

I've been wondering, why is it that so many cryptocurrency exchanges are banned in the USA? I understand that regulators are concerned about money laundering, fraud, and other illegal activities, but it seems like a blanket ban on exchanges is a bit extreme. Is there a more nuanced approach that could be taken to ensure the safety of investors while still allowing for the growth and innovation of the cryptocurrency market? Or are there specific exchanges that have engaged in illegal activities that have led to the broader ban? I'd love to hear your thoughts on this topic.