"I have never expressed a "repulsively racist idea," or you would be able to produce it."

I don't know who said this but on the face of it, it is true. The key is the use of the word "repulsively" nearly no one is repulsed by their own ideas. On the other hand, the use of the qualifier "repulsively" provided a strong indication that the speaker has expressed racist ideas which they do not consider to be repulsive.

Since most people who would use the word racist in any sentence which does not include a denial of racism would consider any racist remark repulsive, the quoted statement, from that point of view is also untrue on the face of it.

I can't imagine anyone but a racist making that statement. But maybe that is simply a limitation of my imagination.