Alright, but still. The ability for some party to block or stop a transfer would make cryptocurrencies not be cryptocurrencies anymore, the topmost reason crypt

Alright, but still. The ability for some party to block or stop a transfer would make cryptocurrencies not be cryptocurrencies anymore, the topmost reason cryptocurrencies exists in the first place and the reason they are built the way they are built is precisely to have the feature of "unstoppable transfers". Changing that and you might as well use banks as we already have "electronic cash". Using that as a argument against cryptocurrencies is a bit like using "but the water irrigation system is using water" as a argument against irrigation systems, it's the main point of using it in the first place. We can't add selective control to allow just government agencies to stop cryptocurrency transfers, it'll eventually be used by others, one way or another. The only way of stopping anyone from being able to straight up manipulate the chain is to disallow anyone to manipulate the chain.