Facebook is reportedly testing a Satire Label on articles from satirical publications such as The Onion in select peoples' Newsfeeds. Given how frequently hoaxes spread online, or how even smart people sometimes fall for fake news articles, there might be an argument to be made that including this might help increase internet transparency. While virtually everybody has heard of The Onion which has been entertaining users for well over a decade now, there are many lesser known fake news sites out there that can deliberately spread misinformation that fool even (lazy) mainstream journalists.
One can understand that this is sometimes annoying. However, people frequently use satire to make a point about politics and get people to think about things in a way that they otherwise wouldn't have and pointing out that something is satire diminishes its impact. Satire and fake news can also be rather amusing, and seeing the satire tag before you've had a chance to read something can ruin the joke.
The biggest potential problem with this though is that this is eliminating the opportunity for people to think for themselves. Life isn't handed to you on a silver platter. When you're walking in the supermarket, no magical label drops from the ceiling that says "buy that fruit because it's healthy for you" or "don't buy that ice cream because it's not healthy for you". Anything that removes the onus on people to think for themselves about what they see dulls people mentally and that's one of the last thing that society needs.