Because even if there is not an individual complainant, there is ALWAYS a 'victim," even if that 'victim' happens to be society and the fabric of the social network.
Victimless Crimes - 1990 is rated/received certificates of: Australia:M USA:R
Victimless crime
The Practice - 1997 Victimless Crimes 4-7 is rated/received certificates of: Netherlands:12
Dennis Miller Live - 1994 Victimless Crimes 2-4 was released on: USA: 11 November 1994
The Practice - 1997 Victimless Crimes 4-7 was released on: USA: 14 November 1999 Hungary: 13 July 2010
The cast of Victimless Crimes - 1990 includes: Craig Bierko Larry Brandenburg Peggy Dunne Mark Maj as Art Patron Debra Stipe
Public Order Crimes
Statistically there is none - because no one has ever complied a comprehensive list of so-called "victimless crimes" or described what they are.
Drugs, Gambling, Prostitution, and Euthanasia
A victimless crime is a term applied to a crime which generally has no direct victim, (e.g.: as in the crime of illegal possession of drugs). Victimless crimes must be truly victimless. In many ways, a false statement offense is considered a victimless crime, but in which, society at large becomes the victim. The victim, for purposes of a victimless crime, is the societal interest that has been harmed.
Crimes which don't harm anyone excluding, possibly, yourself. Doin' drugs is a pretty good example of this.
You would say "les crimes dits sans victime" in French.