I'm so sorry you were treated this way by the police. There is no valid excuse. When police preemptively treat anyone who reports a sex crime as a criminal and threaten prosecution they are in effect doing preemptive witness tampering and preemptive witness intimidation.
For too many investigators when this witness tampering works at convincing victims that the police cannot be trusted their bigotry either allows them to assume they were right to treat victims as the only criminal or witness tampering was their intent all along and they were not interested in seeing a rightful prosecution in a particular case.
Two organizations come to mind as possible resources for you if you are in the US: http://www.victimrights.org/ and http://www.womenslaw.org/ The second 1 has a free hotline.