My evidence for this is that there are people on other apps, including YouTube, who encourage bad things. For example, the Momo Challenge Hoax. A self-harm challenge. It encouraged little kids to cause self-harm, suicide, or violent attacks. Eventually, kids started doing it, and it soon had grown popular.
Despite this, YouTube has not been showing anything like this in the past few years. All you would see would be entertaining content and other people's talents- like juggling, singing, dancing etc.