It's understandable why they do that, but it can put journalists/writers of articles with clickbaity headlines in a tough spot, as they are often forced to defend headlines they never wrote in the first place!
Tell me about it :-) I do the headlines for pieces I write and obviously no one's going to change them on my own blog. But I do write for other venues as well--and I admit I'm not the world's snappiest headline writer--and they do sometimes get changed to things that don't quite match the content of the article.