They do! Fear, anger, and outrage create a rush that stimulates your reward circuits with dopamine, in the same way that a thrill ride or a good workout do:

https://www.psychologytoday.com/blog/culture-shrink/201508/a...

They also cause the release of cortisol, that depresses your immune system, unlike healthy behaviors like spending time with your friends or taking a good walk in a park.

At some point you should start getting bored with it. Same with porn. For a while it's interesting but then it just gets boring. Obviously I have no first hand experience watching pron. I only repeat what I hear from others :-)

Thing is that while the addictive use becomes 'boring' after a while (desensitized), an addict will still continue doing it. Often will go more extreme trying to compensate. Goes for porn, heroin, adrenaline and probably social media.