your subjective opinion
~
it is only your subjective attitude
your subjective evaluation ~ just your opinion

What is acceptable then? Confiscate the coin?
This is a very controversial story because it is based on ideological differences. In a human way, we do not see anything wrong with crypto-anarchism and all its tools, but as an organization we are obliged to adhere to generally accepted norms. And in the case of exchanging cryptocurrency for fiat currencies, it loses most of its decentralized advantages.
Let's isolate
this case: the user wanted to exchange Bitcoin for Monero, and the exchange confiscated 10% of his funds. This has nothing to do with fiat currencies, it's clearly not AML and I bet there are no authorities involved.
@Best_Change: Is confiscating 10% acceptable to you? And if so: based on which laws in which country?