Men should not be allowed to hit women, For their superior strength should be used to protect wome. There is nothing wrong with women giving men a soft slap on the face for rude or sexually inappropriate behavior. This logic can also be applied to sports and arguably the military. Women should not compete with men in sports for they are disadvantaged by the difference in physique. Women can fight for the country if they want but should be exempt from the draft.
The term "double standard" simply means that there are two standards being applied on the basis of a distinguishing set of characteristics. These characteristics don't have to be sex. For example we may have a standard of putting someone in prison for at least 10 years if they are convicted of murder. We have a different standard for people who are acquitted of the charges in a murder trial, Those being to let them go free. There are two standards here, Or a "double standard" predicated on the basis of the outcome of a trial.
Sex is not an altogether bad basis for many double standards as there are actual physical differences between men and women. You would not want to invest money in an advertising campaign for tampons that target men, For example, But you would if it targeted women. That's because women have an actual biological use for tampons, Where men do not.
A rule or principle which is unfairly applied in different ways to different people or groups.
'unfairly applied', Well that doesn't sound very acceptable to me. I have never heard of a double standard which I would classify as being acceptable. (please comment if you have one though, I'm really interested to try find one).