re: Libertarians: how much power should employers have in firing workers?

Jeaux, why do you think that aggressive violence is more moral than prejudice?

I dont think most of the people commenting here (me included) like the idea of discrimination. The question was framed asking if an employer should have "the right" to fire employees for those reasons. There is distinct, though sometimes small, difference in the "right to" and "should".

The question is implying, should the employer have the power, meaning, should the government step in.

The government should not step in because the government will not make things better. We as a society should punish people that act in an inappropriate manner in the way a truly free society should. Either stop using the service of the business or stop associating with those people.