I mean machine learning can only make simple inferences, amplifying our biases as a side effect, but the good news is that it can only make simple inferences, so for a long while it will be people pulling the actual trigger, not a conniving AI itself trying to turn us against each other. Machine learning can be weaponized in many ways from semi-autonomous drones to creating more efficient propaganda more efficiently, but it's our biases, our cognitive constraints are what's killing us. Our world is built on finite material resources fueling limited mental ones, it's only natural that eventually it all returns to nothing, tumbling down, tumbling down.
A conniving AI would be funny in today's computing environment where programs usually run as interruptible operating system processes. If a SIGKILL doesn't do it there is always holding the power button for 3 seconds, or an axe.