Since KING has gone radio silent on this issue and they aren't providing us with any information we are left to our own guesses and opinions. In that light here is my take on this...
I noticed something funny a week or two ago when the latest changes to the game were introduced. The new layout was very obviously set up for play on mobile phones & ipads and not on a computer or laptop. You could tell because everything was more vertically or "portrait" oriented instead of the old landscape. It was very annoying b/c if left at default the game field was VERY small and hard to play on if you don't have stellar eyesight. That meant I had to zoom page in a bit, and when I did that then I couldn't see the menu's at top and bottom like I should be. You had to end up scrolling for just about everything you needed to click. VERY annoying. I thought then that something was up.
Fast forward to yesterday when the game disappeared. After searching around a bit I found that when you go to the KING Candy Crush page and try to click "Play" it goes to a page that just gives you option to load the game from Google Play store, etc... This confirms that they are only supporting play on mobile phones & Ipads now. There is NO mention of FB Gameroom at all anywhere.
It's my opinion that KING has gone the route that many game companies have and they've pulled the rug out from under us with no warning. They are streamlining operations and cutting costs any where they can. Not having coding for FB Gameroom as it used to be separately from coding for mobile apps is one way to cut costs greatly. Less pay to coders, less pay for any support, etc. KING has shown they don't care one iota about the player base and their satisfaction with the game/company. All they care about is the bottom line profit they can drag out of players.