The British bank HSBC
recently had over $500,000,000 laundered through it. Banks have had huge problems attempting to prevent illegal activity.
Furthermore, this relies on the assumption that the law is necessarily correct and ethical. The law differs between many different countries and in each, banks legally have to abide by these laws. Hypothetically, if the government said that no one could have a credit card anymore (alright, they wouldn't have a reason to do that, but there's all sorts of things that they
do have incentives for), what could the banks do except abide by the new law?
A decentralised system doesn't rely on legality, and monetary systems shouldn't have to. Illegal activity is a side effect of money that is free, just like cash, but it's not the entire reason for it to exist.
I think that people like this can do a much better job of criticising BTC with
actual criticisms. That's why I hang around
r/buttcoin sometimes - to get a negative point of view that actually makes sense.