Many software vendors want to impose security and encryption basically everywhere. Google and Mozilla are two of the more vocal organizations about it, and they have been slowly implementing ways to discourage insecure HTTP (in favor of HTTPS). Some of these make sense, like preventing insecure sites from accessing your webcam so the video stream cannot be intercepted, while others seem a bit pushy, like lowering HTTP-based sites down in search results.
This announcement's change is technologically benign, but is designed to make HTTP feel a bit uncomfortable. Rather than just promote HTTPS sites with a secure padlock symbol, Google Chrome 56 and later will begin to add a “not secure” label to HTTP sites. At first, Google claims that it will only mark sites that transmit sensitive data, like passwords and credit card info. They intend to expand this to all HTTP websites going forward.
Again, this has pros and cons. The main benefit of encryption is that it's much harder to view or manipulate what flies across the data stream. One major disadvantage is that the content needs to be authenticated, which is a concern for truly anonymous expressions. Google Chrome treats local, offline content as secure, but that use case could be easily forgotten, and that could have terrible rammifications, especially in areas controlled by oppressive governments that massively censor art.