iV) Affirmative action is racist

It is racist. there is no Issue here . Indeed the bad argument is yours. You argument appears to be that if something is 'good' then it can't be racist. This is just incorrect. There is nothing that implies morality within the definition given in English lanaguge dictionaries apart from those published by the Marxist left (whom I implictly reject).

The problem here is not that Yvain has made flawed arguments but rather that you incorrectly interpreted the post.

Yvain is not arguing that affirmative action is or is not racist nor is he arguing about whether affirmative action is good or bad. He is pointing out that the (implied) argument in the quoted claim is flawed for the reasons specified in his introduction. Nothing you say here justifies the claim that "The bad argument is [Yvain's]".