In case of YT it is likely a mix of multiple reasons. They stop playlists on this screen: https://www.hollyland.com/blog/tips/why-does-this-the-following-cont

In case of YT it is likely a mix of multiple reasons. They stop playlists on this screen: https://www.hollyland.com/blog/tips/why-does-this-the-following-content-may-contain-suicide-or-self-harm-topics-warning-appear-on-youtube https://www.hollyland.com/blog/tips/why-does-this-the-follow... . Apparently music is no longer advertiser friendly. Detecting ad-click fraud is easier when users are at least pseudo-anonymous. Warnings about "ban for using adblock" is also not very effective when people could watch video in new private window.