Can a SIMD system be really considered "multi-threaded"?
SIMD = Single Instruction Multiple Data, meaning the same instruction being applied to multiple different values simultaneously. That's exactly what GPUs do.
That being said, I understand you only wanted to point out the error in the upper post.
It did acknowledge the title, and contrasted it with the tone of the article (the first half at least) which is way broader minus a mention of GPUs (the basics of parallel algorithms, parallel APIs).