When you want to make legal arguments, you do it when you have good facts, and this is not that time.
The facts about Tornado cash are terrible: pretty much everyone using it is either doing something provably illegal or trying to avoid being found, you have to go out of your way to use it (and pay an extra fee), and it's been part of a large number of bad news stories about crypto theft. A minimum of 10% of its throughput is provably due to frauds and thefts, and probably a lot more. It is not an exaggeration to say that many people's life savings have been funneled through Tornado cash into the wallets of criminals. In comparison, numbered Swiss bank accounts likely had more legitimate use than Tornado cash.
In comparison, the facts about Monero, Zcash, and the Wasabi BTC wallet (another mixer, but attached to a wallet) are a lot better. Privacy is free and/or the default option with those services, and they are a little more like cash: lots of victimless crimes (darknet sales, etc.), some use by ransomware attacks, but also a lot of legitimate use.
This lawsuit has a nonzero chance of throwing out the baby (privacy on blockchains) with the bathwater (tornado cash).
25% of funds being illicit does not mean “pretty much everybody” is using it for illicit reasons. Your argument really falls apart here, but the sweeping generalizations don’t help.
Monero and TC are equal parts useful for non-criminals who are seeking privacy.
The facts about Tornado cash are terrible: pretty much everyone using it is either doing something provably illegal or trying to avoid being found, you have to go out of your way to use it (and pay an extra fee), and it's been part of a large number of bad news stories about crypto theft. A minimum of 10% of its throughput is provably due to frauds and thefts, and probably a lot more. It is not an exaggeration to say that many people's life savings have been funneled through Tornado cash into the wallets of criminals. In comparison, numbered Swiss bank accounts likely had more legitimate use than Tornado cash.
In comparison, the facts about Monero, Zcash, and the Wasabi BTC wallet (another mixer, but attached to a wallet) are a lot better. Privacy is free and/or the default option with those services, and they are a little more like cash: lots of victimless crimes (darknet sales, etc.), some use by ransomware attacks, but also a lot of legitimate use.
This lawsuit has a nonzero chance of throwing out the baby (privacy on blockchains) with the bathwater (tornado cash).