Argument: X is bad because Y. Counter: But Z is also bad because Y and I don't hear you saying anything about that! Conclusion: So X isn't bad.
E.g. the typical Soviet whataboutism:
Argument: The USSR doesn't respect human rights and that's bad. Counter: A u vas negrov linchuyut (but at your place, you lynch negroes). I.e. the US doesn't respect human rights either. Conclusion: So the USSR isn't bad.
The mere presence of Z does not invalidate the argument that X is bad because of Y. It's irrelevant, which is why tu quoque is just that, a fallacy of relevance.
Inconsistency in these kinds of areas just makes a mockery of the legal system and encourages corruption.
There are tons and tons of other problems with this proposal I didn't get into, such as how cryptocurrency is defined. Are we going to start making data structures like linked lists of cryptographic hashes illegal? In-game virtual currencies? Amusement park tokens tracked in a database? Any law would be either overly broad or trivially circumventable.
Real or perceived hypocrisy doesn't absolve cryptocurrencies in any way. What they are and what they have to account for has to stand on itself, on its own.
Two wrongs don't make a right.
You also seem to be a bit disingenuous: cryptographic hashes don't boil the ocean. Amusement park tokens idem. They aren't used for ransomware.
So this attempt at some kind of slippery slope argument isn't really working, if you would ask me.
When money is at stake, logic and reason is the first to fly out of the window. Whatever necessary to make the grift going will be said.
For just one example, look at how hedge fund and foreign capital speculation in housing is making a home unaffordable for millions upon millions of people and contributing to middle class decline and homelessness.
It's a bit like making pot illegal when hard liquor and cigarettes are legal. What it really amounts to is the existing parasitic financial industry using the state to remove a competitor to its own gambling and destructive speculation operation.