I already know that killer whales attack great white sharks. I'm only interested in reading the article if it's about some other predator, but they deliberately omit the identity from the title to force me to click to find out. That is clickbait.
I just want to be able to browse a news aggregating site and have a rough idea of what the article is about. So why have me click on the article only to find out "oh, it's about interactions between great whites and orcas" when you can just put that information in the title.
Sure, if I'm clicking on anything fish-related anyway that may not be a problem. But the title as it is phrased now clearly leaves out a key bit of information, namely who this predator is. That's disingenuous and the reason why I support calling it out as clickbait (i.e. "click on this link just to find out what it is actually about!")