What distinguishes unlawful discrimination from lawful discrimination?
Many decisions that are made in the course of everyday life can be said to be discriminatory. For example, you may prefer vanilla to strawberry ice cream. That type of discrimination is a matter of personal choice. The strawberry growers have no civil rights claim against you.
A life insurance company charges lower rates for 20-year olds than 60-year olds, and this is permissible. The Government treats bank robbers differently from bankers, and bankers differently from bakers. That does not mean that there is unlawful discrimination.
Decisions become unlawfully discriminatory when race, creed, national origin or ethnicity (and, in some cases, gender) are factors which cause one person to be treated differently than another. Some states have laws that also protect against discrimination on the basis of marital status or sexual preference.