This phrase comes from the world of online gaming, games such as World of Warcraft.
These games provide a mechanism called emotes for players to express emotions or indicate physical actions. For example:
"Sean scratches his nose."
Power emoting describes the abuse of this system when players use emotes to describe an action that takes away the ability of another player to respond or prevent it. For example:
"Sean picks John's pocket and steals his wallet."
"Sean cuts off John's head and throws it in a ditch."
These are considered god emotes because John cannot prevent the actions from happening. Here are corrected versions of the above examples:
"Sean puts his hand in John's pocket and fumbles for his wallet."
"Sean swings his sword at John's neck."
John can respond by catching me in the process of stealing the wallet or by blocking my sword.
"Sean casts a spell that causes the world to end, killing everyone!!!!"
Hey, you can't do that you noob. That's god emoting.
"Sean kills everyone again because they are noobs!!"
Just go away Sean, this is stupid