Google's John Mueller said on Twitter that "lots of SEOs & sites produce terrible content that's not worth indexing," when someone was complaining his content was not indexed. "Just because it exists doesn't mean it's useful to users," he added.
It is really hard for SEOs and/or site owners to believe their content is not terrible. Heck, some or maybe a lot of the content I produce is borderline terrible. But maybe, just maybe, a benchmark for if your content is not terrible is if Google spends the time to index that content.
Obviously, it should work the other way around. You should produce content that you know is quality, that is not terrible. Then Google will figure it out and index it. But at the same time, if your content is not being indexed, or some of it is not being indexed, and it is not a technical issue, then Google thinks the content is not worthy of being indexed.
If your content is not indexed, does it make your content "terrible"? I am not sure I'd go that far. But it does not meet the quality thresholds for Google to index the content.
Here is John's tweet in context here:
Well, lots of SEOs & sites (perhaps not you/yours!) produce terrible content that's not worth indexing. Just because it exists doesn't mean it's useful to users.
— 🥔 johnmu (personal) updated for 2022 🥔 (@JohnMu) August 16, 2022
Forum discussion at Twitter.