Your first sentence seems mis-worded, but there are two answers to your question.
Firstly, it's unethical and morally abhorrent to discriminate on the basis of age, heritage, and gender in general employment markets.
Secondly, the laws exist making illegal these types of hiring discrimination because ethical behavior doesn't come naturally to many people making hiring decisions.
The very-sheltered may have never seen it, but there is a great deal of bigotry out there.
The history of these issues for workers is ugly and bloody. People died to get us to where we are today.
Firstly, it's unethical and morally abhorrent to discriminate on the basis of age, heritage, and gender in general employment markets.
Secondly, the laws exist making illegal these types of hiring discrimination because ethical behavior doesn't come naturally to many people making hiring decisions.
The very-sheltered may have never seen it, but there is a great deal of bigotry out there.
The history of these issues for workers is ugly and bloody. People died to get us to where we are today.