Irrelevant relateds, not category specific even

I view a post “Optimus G Metal bumper”
Yet in the list i see all “iPhone 5 Metal Bumper”, or “Optimus P790”

I have over 20 other “Optimus G” posts, why does it not list them at least?

Why is there not a “category specific” tick somewhere? I would think people would use it.

https://www.ads-software.com/extend/plugins/yet-another-related-posts-plugin/