Sorry, but that is not legally correct. Discrimination is illegal only for certain named “offenses.” Race, color, creed, nation of birth, gender, disability etc.
I can fire and/or not hire any person or group of people as long as they are not in a protected class. I can refuse to hire red-headed people, land-handed people, liberals, smokers, Michaganders, Dems, etc.
Many states recognize a tort of wrongful termination in violation of public policy. In many states, for example, an employee can sue for wrongful termination in violation of public policy after being fired for (1) exercising a legal right, such as voting, (2) refusing to do something illegal, such as submitting false tax returns or lying on reports the employer is required to submit to the government, or (3) reporting illegal conduct.