of course they are. Americans can't make a penny without Uncle Sam taking a look so he can get his bite.
If we are not funding horrible things, then we should be able to do what we want with our money.
Americans are going to have trouble hiding any currencies from the IRS long term. Anything they can't dig into they will ban us from trading.
RE: IRS has been tracking Bitcoin usage since 2015 & List of Coins that Can Save You from Spies.