Bad PIDs, plus youtube trying to stabilize for him I think.
My kingkong Q100 build (~38g no battery) with 14.7kv motors, afunta props, and a mpu6000 gyro running 8K gyro 4K PID loop, ended up at 110P 160D.
Raise P till you get small very fast oscillations (as opposed to the large/slow in the video), then raise D till they go away.
No active braking, so high D won't roast the motors like brushless.
That's the really, really, very, extremely condensed version of @NotFastEnuf style tuning, which has generally worked great for me.