So it’s awkward to make the distinction (“I think not being racist is the new racism”), but based on that article, it does seem to be the first romantic kiss–I know it’s mind control in the episode, stop picking at me mid-sentence–on US television between black and white people specifically. The previous examples were arguably less taboo for their time, being between Hispanic and white and Asian and white partners. They each represent their own milestones.
I think part of the confusion probably comes from the fact that “interracial” is sometimes used specifically to refer to black and white pairings, so when people say it’s the “first interracial kiss”, that is what they mean. This is an incorrect usage and dismissive of other interracial pairings, but I don’t know if there’s a more specific word for different pairings and you sound like a creep drilling down into the subject this much, as you can see from this comment right now.
Maybe they’re just leaning into the Mastodon theming by talking like cavemen.