Just as a lie is a lie, racism is racism. We have all lied and some point and I can bet we all have been racist at some point as well.
It just matters how you act in your opinion. Obviously, if you are feeling someone is being an ignorant asshole, you don't need to call them something you know is directed at their race... "Ignorant asshole" works just fine. I don't like using that word simply for the people who were enslaved. I could give a crap about the teens and 20 and 30 something year olds that think they have the right to plead "BUT SLAVERY". I feel bad for the ones that lived it.