I talked to several (non-tech) friends about this, and they were more upset about Facebook "censoring" out posts than the emotional manipulation.
YES. This is exactly the problem.
Those of us who understand the tech already understand that Facebook's Newsfeed is not a 'dumb pipe' and that it runs an extremely opaque and proprietary filtering algorithm. We realise that a lot of posts get silently dropped; we constantly switch from 'Top Stories' to 'Most Recent' to try to counteract this. Many of us use Twitter instead and crosspost to Facebook because we know that Twitter tends to deliver all posts rather than silently screen them.
But non-tech-savvy people - our parents, grandparents, cousins, aunts - don't realise this. They think that the posts they see on the Newsfeed are exactly and only what their friends are saying. They think that if they see something with a thousand Likes, it's because their friends like it too. And why wouldn't they? To them, Facebook is a messaging service, not a media service. They know that TV and newspapers filter and select content. But they don't see Facebook as a newspaper. Their prior examples of messaging services are the telephone, post office, and then email - all three systems are ones that place a very high priority, almost a moral imperative, on the message always goes through unchanged without alteration or censorship. If they thought about it - which they generally don't - they'd expect that there was actually something in the user contract that specified this, because hey, isn't that the way things have always been? Isn't there something in the Constitution about freedom of speech? They don't realise just to what extent the Facebook terms and conditions say 'we reserve the right to hide posts from you, and not pass your posts on'. They don't realise that Newsfeed is far more like Rupert Murdoch paper than the Post Office.
That's the scandal here. It's shocking and it should be shocking to all your non-techy, non-cynical friends to see Facebook proudly talking about how they deliberately manipulate people's Newsfeeds to not actually be a representative sample of their actual friends' actual posts.
Keep the focus on that. The scandal is about censorship, free speech, and trust, not the esoterica of experimental protocols. It's important.