Earlier quoted context omitted.
Under US law, no. Money laundering requires the intent to conceal the origin of proceeds from certain specific unlawful activities or to avoid financial reporting requirements. Hiding the origin of lawfully obtained money is legal.
This is absolutely not true, at least in the US. If you are a business that transmits even 100% lawful funds without registering with FINCEN and registration as a MSB in your jurisdiction, you can and will be charged with money laundering.
Simply using a tumbler is not illegal.
For instance, if someone used legally obtained money to buy bitcoin, put them through a tumbler, then used the bitcoin to buy drugs. That would not be money laundering because it does not hide the proceeds of a crime or avoid any financial reporting requirements.
On the other hand, if the drug dealer took the bitcoin that they were paid with and put it through a tumbler, that would be money laundering because they would be hiding the origin of the proceeds from selling drugs.