Is a racist joke discrimination

Answer 1

Not in and of themselves. They are racist. Look up the difference between racism and discrimination.

Discrimination is unequal treatment. Racist jokes can be used in a discriminatory manner, if they create a hostile environment. If someone feels harassed because of jokes told at their workplace targeting their race (particularly when members of at least one other race are not targeted), and such behavior is allowed or even institutionalized, they could sue for discrimination. Some comedians seem to get by with this because they are equal opportunity offenders - the offend every group equally. They don't discriminate; they are just bigots.