It’s much more the clickbait aspect. Post just enough to bait someone to click for the rest of the story, instead of posting the entire thing. Get eyeballs to your website/blog. It’s seems to be more common these days, even when unnecessary. Has nothing to do with the first amendment.
Why do you think this is my website or blog? I saw this story at The Liberty Daily and followed the link from there. And there was no easy way to post the text from there, so I put a few lines. If you read a bit and don’t find it interesting or confusing, bail and go on to the next story. That’s what I do.