One of the ways to avoid a copyright strike is if you copy other people's work, then what you upload must be "transformative" i.e. you have alter that source content significantly. Satire / Parody are two ways to do that.
But the cheapest, laziest way to "transform" content is to do reaction videos to it. And some people don't even do that. They'll just sit there, eating their dinner . . . occasionally glancing at the screen and going, "huh." Lazy jerks.