A racist is someone who sees every aspect of life through the prism of racial consciousness.
To determine if one is a racist would seem to require a great deal more information than a single internet post, or ill-advised joke, or stone-cold honest observation.
To me, the racist is the one who believes one's entire belief system on the races and their inter-relations can be surmised by any single little act.
Someone like that also seems like a simpleton.
Since you have mis-defined racism and called me a simpleton it is hard not to laugh. Yes, one can tell a joke about a race and not be racist.
However, when one attributes things based on race while making fun of them, it is racism.
99% of people here are not racist but every large group has some. Do you believe that you never read racist posts here?