The parent is referencing the "Kafka Trap", which I believe was originally coined on ESR's blog a decade or so ago. This rhetorical construction is used a lot in these kinds of discussions, and, because of its crudeness, is why people tend to get pretty bent out of shape during said discussion.

>One very notable pathology is a form of argument that, reduced to essence, runs like this: “Your refusal to acknowledge that you are guilty of {sin,racism,sexism, homophobia,oppression…} confirms that you are guilty of {sin,racism,sexism, homophobia,oppression…}.” I’ve been presented with enough instances of this recently that I’ve decided that it needs a name. I call this general style of argument “kafkatrapping”, and the above the Model A kafkatrap.

http://esr.ibiblio.org/?p=2122

>Denial is proof of guilt?

It's part of the bizarro "privilege" narratives. In their framework, if you deny the existence of your privilege, you are proving you have it even more, because only a "privileged" person is capable of ignoring the concept of privileged/unprivileged