I believe you. The question is not whether you were fed conspiracy theories, it's how effective were they and "compared to what?" Because that's what's implied by these articles/studies. They claim "people are radicalized," which is very different than "people watched some UFO videos."

How many people watched Youtube videos and were radicalized into believing in flat earth, aliens, etc?

Compare that to how many people watched legacy media and were radicalized into believing that Iraq had nukes and Trump was a Russian agent?