There are two different settings. One is friendly fire, the other is betrayal booting, and they can be set independently.
Right now, friendly fire is turned off, and so is betrayal booting.
But you can still betray with vehicles, both with spatters and by destroying the vehicle which kills the player inside. (In the game that video is from, the dude was just focusing on splattering players, knowing he couldn't be booted.)
I posted this video and asked for it to be turned on last month in the Optimatch forum. I hope betrayal booting is one of the small adjustments made for May. It's a problem on vehicle maps.