When 'color contrast' is mentioned he is referring to the example with the toggle tokens, with widely different brightness for the active (blue) and inactive (l

When 'color contrast' is mentioned he is referring to the example with the toggle tokens, with widely different brightness for the active (blue) and inactive (light gray) states. I suggest re-reading the article, since the author agrees completely with you - your last sentence is a straight paraphrase of this: > If you’re using competing color hues to differentiate states, you need another visual cue besides color. But if you’re only using color contrast to differentiate states, it’s likely accessible to color blind users.