The Massacre of the CPG Cements the Institute as Fallout 4's Villain

gamerant.com:

The Institute is the bogeyman of the Commonwealth. They’re built up to be the main antagonist in Fallout 4, only to have the main storyline turn on its head when the player finally arrives in their underground lab.

The Massacre of CPG is one of the atrocities that took place at the hand of the Institute. It happened long before the events of Fallout 4, and despite Shaun’s promises that the Institute is doing what’s best for the Commonwealth, it’s hard to believe given everything that the shadow organization has done to the wastelanders above.

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The Commonwealth Provisional Government (or CPG for short) was a post-war organization that was first planned by the Minutemen. They called on representatives from the most notable settlements in the area and convened at the Castle. There, they engaged in talks, likely about how to unite the people of the Commonwealth and make it a safer place to live in. It’s unclear who exactly the representatives were, but one of them reportedly spoke for the Institute.

According to data in the game, the CPG persevered for four years. However, it doesn’t seem like it made much progress in regards to cleaning up the Commonwealth. This was most likely due to infighting and, overall, the inability to reach a compromise. By this point, the Institute was growing tired of the bickering. A holotape recording by one of the Director’s staff reveals that many within the organization wanted to cut off all contact between themselves and the Commonwealth.

Others, however, believed it to be a mistake, and that the Institute shouldn’t give up on the wastelanders. The same holotape hints that the Institute already had a sizable army of synths at their disposal at this time,