> And that niche is being a parasite on Google Image Search while offering crap results?

I believe your anger is misplaced, and directed at the wrong target as well. It's Google Images offering the crap results, and I think you already know that. Reddit is also loaded with plenty of low quality content, as is Imgur, as is Facebook, as is Twitter; all large social networks are flooded with epic piles of garbage; Google's search results are clearly the problem re Pinterest images showing up in Google image search.

To answer your 'question,' the 416 million monthly active users very obviously aren't staying with Pinterest just because Google Images has a lot of Pinterest image results.

I don't like TikTok, it doesn't appeal to me. The very short video clips mostly annoy me. I still fully understand why so many people use it. Google indexes their video content - I wouldn't blame TikTok if Google's video search turns to crap over time due to that, I'd blame Google.

OTOH the same logic would be to blame google when sites are using blackhat SEO. AFAIK pinterest does do greyhat (at best seo): they scrape images, feed them to google image search to get the best tags, and add then to the post.

You're saying that asking Google which terms best describe the pic, and writing that down next to the pic, is unethical SEO? At most it's some kind of theoretical IP infringement on Google's image recog algorithm.

I'm not talking about content quality!

When I find an image on Google search and I want to go to the source site, I want to see that exact image there.

Not scummy paywalled "I show Google something else than you" images.

Plus it's pretty obvious that in many cases they scraped the original, which then they outrank in SEO.

Google controls the Google preview, not Pinterest.

Pinterest is serving different content to the Google crawler than to Google search users.