People would take something that "may" be in the next patch and mistake it for actually "being" in the next patch. Then they slingshot it through twitter, facebook, instagram, and you end up with a huge mess. Then the pmbr has to backtrack and resolve the issue.
I saw this same thing happen during the Starcraft 2 Heart of the Swarm Beta. Everyone was going ape **** when Blizzard gave tempests like 22 range. They were too dumb to realize that this was just a "test" and that these things would eventually be changed.
To take a quote from a riot post
"Keep in mind that the forecast is more about identifying problems that we're looking at, and not promises of changes to come in each patch. Some changes might take longer than others!"
Alot of the reasons people can be upset is if developers don't acknowledge things. Even without promising change, taking responsibility for the current state of the game and communicating with your players is important. Players want to know that they've been heard, even if they're being taken with a grain of salt.
Alot of people care about this game. Because of that, people care what direction it's taking.
When developing for a large audience of ongoing players, it's important that you communicate with them, because you ask them to care so much into a game that's going to change. Of course they're going to care about the changes that are being made to a game they have so much investment in.
No, it's not necessary to communicate, but perspective is important.