I'm guilty of doing this (just reading the headlines) as well. I usually do it for these reasons:
I don't care enough to want to read more. For example, news about US politics. I don't live in the US. I feel that reading the headlines is enough to keep me informed about what's happening, but I really don't care any more than that.
The details aren't valuable to me. For example, the Apple anti-trust lawsuit... Is it important? Yes. I'm already well aware of the horrible anticonsumer practices of Apple. But do I need to know all the particular details about the lawsuit? Not really. In fact, the only thing that matters is the final verdict, which hasn't happened yet.
I care, but I already know enough details.
I don't feel like the article would bring a lot of value, especially if the title is click-baity. I've encountered too many articles that are void of content, just the title repeated in 10x more words.
I don't like visiting news sites because, in addition to all of them being obnoxious and ad riddled, I feel like I'm wasting a lot of time reading long articles that could be rewritten as 3 bullet points. On platforms like lemmy, users will highlight the important bits in the comments which saves a lot of time.