That wouldn't help. A significant metric Google uses for ranking is relevance, meaning number of historic clicks for a given search term.

As users learn that Reddit links aren't useful sources of information, they'll click less, which means the relevance between the search term and Reddit goes down. Ultimately reducing Reddit's ranking, regardless of if the Googlebot is allowed to index the content.

People often mix up indexing and ranking. Indexing is if you're even in the results set, but ranking is where. Reddit might, technically, still be in the results set but if it isn't on page 1 for a given search it may have well not be.

Hasn't stopped Pinterest from flooding google image search results.

Pinterest needs to be blacklisted from search engines. I'm never signing up for an account there, period.

lol, reminds me of the image search I did last week to find some earrings for my mom. "celestial earrings threader -amazon -etsy -pinterest -aliexpress -alibaba -dhgate"

The internet is becoming a friggin pain in the ass.

Reminds me of eBay, and how I try to find parts and accessories specific for my old car. I used to be able to just type in the make, model, and year, and BAM, I had tons of results. But eBay has allowed peddlers of low-quality, generic junk to spam their listings. Now I have to search "1981 Honda Accord -fits -turbo -generictrash -etc" and filter out every single part that comes up 1000 times that isn't actually even designed for my car. They just call it a "generic" part and list that it fits every car. I used to search eBay regularly, and now I hardly go on there anymore because I can't find anything.

It isn't a great analogy. Pinterest still provides the content people were after on Image Search (the image). The only thing you cannot do is click it and see related images.

A better analogy might be Expert Exchange. A site that put answers behind a paywall, and fell hard out of Google's search results. Then Stackoverflow came along and took whatever remained.

Google will figure the higher bounce rate of the page (the user quickly went back to the SERP) means it's not as relevant as they thought, so they'll move it down in the search rankings.

The Pinterest issue has been there for 4+ years. When does Google figure it out?

Maybe it's not an issue for everyone? Maybe the bounce rates on average aren't that bad and some people are spending lots of time there? It's possible, but I agree they aren't very user-friendly in search results for someone who doesn't have an account. I also avoid them.