They are reacting to the short videos from regretful trump supporters at the beginning. It’s even called a reaction in the thumb nail. Thinking about it, what even is the difference between commenting on and reacting to someone else’s video, if the commenting is done by showing their videos and then making your own video about it?

What I meant is the appeal to watch them (I know that was probably clear, but I’m still interested)

I don’t understand those reaction videos. Could be because I’m autistic. Can someone explain their appeal?