This has not been my experience, nor my wife's experience. Instagram shows more of what you click on, so it's entirely possible you are clicking on trash, so they're showing you more trash. From what I've seen, it does a pretty good job of reflecting your viewing habits.
Sorry, should have clarified that I'm referring to Explore. I figured if someone is complaining about bad content on Instagram, it's in reference to content they don't have control over.
