With competition it is a red queen's race unfortunately. It is natural in an emergent sense even though the circumstances are synthetic. If they don't someone else will and even if they held existing jobs sancrosanct they will be displaced by a new party who doesn't have existing jobs to protect.
We don't get to choose whether we're in the race or not, but we do get to choose how we run it. I get the "these are forces at work, not humans" argument, but I think it underestimates the solution space available to the humans in the scenario (to be fair, they probably do too).
Nature is pretty damn cruel and selfish at times. Just because it utterly sucks doesn't mean it isn't natural - similarly healthy has the question of healthy for who and when?
Illness in herd animals is healthy for wolves by making them easier to kill without injury.
The industrial revolution saw major growing pains and destitution but raised standards of living greatly.
Your somewhat patronizing analogy misses the point. If our ultimate goal as a species is to survive and live well, then cutting hundreds of thousands (millions, actually, if you think about the implications of automation in other areas) is in conflict with that goal, thus 'unnatural'.
Software agent aka bot is not a robot. Robot is physical device. ATM is more robot-like than chatbot.