Good point, I didn't think of it that way. That could well be the explanation.

But it's still pretty sad that white people feel so vilified and demonised. It's silly, given how much whites have given the world.

I think it does explain it, but in a less direct way. If you search for "couple" without any adjectives, you'll find mostly whites since there's little reason for whites to tag/describe themselves as whites (but blacks do label themselves as black so you need to specify it when searching for black couples) On the other hand, if "white" is used it has to be because there's something odd about the image that merits the mentioning of race, meaning: interracial couples, white weirdos who identify as black, etc. Basically, if "white" is used to describe an image, it's most likely because there's someone not white on it.

What I think this proves is how contentious and politicized the term "white" has become. And the power of clickbait I guess.

This is partly – probably largely – due to the way that images are tagged. Black Americans get tagged with "African-American", rather than just plain simple "Black", because RAAAAACISSSS!!!, but whites and others don't.

If you do a search for "happy couple", by contrast, you get a lot more diverse results – plenty of white faces.

However, this does not explain why searching for "white couple" gives us so many mixed-race and gay results.

Tried again in Japanese, panicked and closed the window

I know better than to try that out myself – I have no doubt that the results will involve copious numbers of japanese girls who look ridiculously young, dressed up in Sailor Moon outfits, and let's just say that there will likely be tentacles involved…

the rest of the world is convinced we are all black.