Uhh idk

I've been playing DBD for about two weeks, give or take, and it was only recently that I encountered a Ghoul player. Believe it or not, I'd never played against him before or even knew what his abilities were, so I just played like he was any other killer.

I was doing a gen when the killer suddenly appeared out of nowhere and proceeded to down me. I expected him to hook me, but that's not what happened. He just left me??

After a teammate helped me up, I went back to doing gens. But when I got downed for the second time, he left me again?? I was very confused and thought this was just one of his abilities or something.

Then, after that, all of my teammates got downed. I was honestly pretty perplexed because I'd never encountered this strategy before, and it seemed really effective.

After a quick Google search, I found out this strategy actually has a name which is slugging.

So I'm wondering, why don't all killers do this?