These lists of personal characteristics are called prohibited grounds of discrimination in employment. In the United States, the same lists are called protected classes. If the personal attribute is on the list, the employer must be blind to it. One cannot consider that attribute in any decision unless the attribute can be clearly demonstrated to relate objectively to the job. For example, if fire fighting requires extraordinary physical strength to do the job, fire departments might justify fitness testing that disproportionately screens out disabled, elderly, or female prospects. Likewise, safety concerns in a construction site might override religious beliefs if the worker will not wear a hard hat.
Equality through non-discrimination is a social construct, given effect through law. The model which Canada has chosen to use is the prohibited grounds of discrimination framework. It is thought to provide more specificity and efficacy than simply to legislate that everyone is equal before and under the law. However, one might ask whether the list of prohibited grounds of discrimination is itself discriminatory.
If we compare the current lists of prohibited grounds of discrimination against these three criteria, we will find some which do not warrant being there. For example, ancestry, place of origin, ethnic origin, and race seem unnecessarily duplicative. In contemporary multicultural Canada, is one's ancestry or place of origin really visible and a factor in employment decisions compared to race or ethnic origin? Is sexual orientation visible? What about religion? In Ontario, why are citizenship and record of offences not relevant in every employment? One might argue that they should be permitted grounds of discrimination.