If you ask me, they should all be shut down for selling unregistered securities, because all crypto tokens fit closest to that definition more than anything else. It's impossible for these tokens to actually function as a currency, both technically and legally. They're not a new class of assets, the idea of tradable tokens is not new either.

To add some nuance to the sibling reply, the SEC has extensively laid out its legal argument for why many (not all) of the coins traded on crypto exchanges are securities under US law, including specific examples. See the recent insider trading complaint [1] and this analysis [2]. Dealing in unregistered securities is a crime [3], so if the analysis is correct then the exchanges are breaking US law.

[1] https://www.sec.gov/litigation/complaints/2022/comp-pr2022-1... (¶ 95 - ¶ 206)

[2] https://www.sec.gov/corpfin/framework-investment-contract-an...

[3] https://www.law.cornell.edu/uscode/text/15/78l