It is not the case that rape is differently treated from other offences against the person. In all such crimes, the lowest standard is one of recklessness. Murder is homicide with 'malice aforethought'. But it would be bizarre to institute a crime of gross negligence rape. Unlike homicide, sex cannot be entered into accidentally or negligently.
Sex is defined by the way it is carried out - on the basis of a conscious decision.
The law recognises implicitly that unlike a homicide, where there is a dead body to account for, the sex act in itself is not harmful. Put more strongly, mens rea is the basis of society's condemnation of the guilty. Critics of the Morgan principle are at best mistaken, and at worst disingenuous, if they argue for changes in rape law through claiming that it is tried differently from other offences against the person. More such amendments to the law would separate rape even further from other offences. Too often victims of rape are told that it is an offence different from any other.