I watch very little YT content. I before Friday, I had never heard about either of these people. I have never seen a react video either.
So, I watched this video. And a couple by jacksfilms. Maybe it is because I am nearing 40, but I don't see the draw of watching a reaction video? Anyway. It is a little amazing that an internet feud has an entry on Wikipedia (here) and after watching the War on stolen content video I am surprised that the concept took off.