Tax for what? yeah sure go ahead and obey them blindly those laws to take your money and spend on weapons and military arsenal with only one goal to kill other people instead of spending them on making sure there is peace in the world.
But honestly what are they doing when it comes to online gambling or cryptocurrencies? are they protecting you from cyber attacks/hacks/theft/fraud?
This kind of tyranny shouldn't be tolerated by any citizens of any country, as you know governments around the world are the minority ruling us the majority and ironically in bitcoin network the majority(miners doing everything in consensus) are ruling the minority.
Bitcoin can not be geographically allocated so it's more like the international waters, if you hide your transactions and business in general using a mixer big and trusted enough such as BitMixer.io no one and I mean NO ONE will be able to link you as a US citizen to any transaction and financial activity what so ever.
Not to mention that US governments are not okay with people gambling in any way, shape, or form that pertains to "luck" or "chance" on casino like games (except in areas like Las Vegas with special "permissions"), but is OK to buy state lotto tickets. God knows how that money, which is collected to fund in state education, is used. The funny thing with cash (which is the only way to purchase lotto tickets) is that it is a truly anonymous/fungible physical form of currency; which allows
the government to be able to spend it on whatever they chose and to be responsible for whatever they deem fit.
To your point about mixers though, I'm not so sure about that. A mixer that is "big" and "trusted" is a centralized source where governments can attack. There are many ways people with resources, like the government, can be able to manipulate the host of the site to comply and cooperate, etc.
If Bitcoin has taught us anything, it is the power of decentralization. Things always tend to want to centralize... you can even see that today with the centralization of mining, exchange sites, etc. in order to be viewed as "credible", which is just wrong. I find it important to keep trying to find a system that promotes a truly decentralized way of being able to exchange a currency online without having to worry about having to go to a centralized mixing system in order to remain "anonymous" or have your currency to remain fungible and not associated with past transactions.