It is not precisely treated as a crime in the US. That is to say, below a certain amount, the police will not raid your house and take you to a judge.
It is more treated like a parking fine. First, the IRS needs to audit me. Then, they need to prove that I actually made this income or spent this income in a certain way that requires reporting.
Once they've proven that, I don't go to jail. I just pay the missing amount of taxes with a 5% penalty.
If I were to buy weed with Bitcoin, that would be a Federal crime. But in some US states and some countries, it actually wouldn't be a crime at all.
So, your criticism isn't as black and white as you think.
