"Telemetry settings in Kibana" indicates that it is about telemetry settings in Kibana. Which is what the article is.
"telemetry.optIn defaults to true" indicates that some setting, somewhere out in the world, defaults telemetry to true. It's a clickbait title.
Poster should have titled it "Kibana Telemetry Is Opt-out" if they wanted it to be a proper title.