Like I said, money laundering is no more a criminal behavior than you using https here.
The definition of money laundering is concealing the source of illegally gotten money.
The point is it shouldn't be illegal. If the govt outlawed the use of encryption then encryption would be illegal too. Making encryption illegal would make it easier to catch and convict criminals and if you can't you could always charge them w/ illegal use of encryption (kinda like money laundering charges are used).