the damage is done. Why did they ever think it was a good idea to brag that they were going to destroy all middle/upper class jobs?

To market their product to c-suite people.

Because it helps to raise capital at low costs if your investors and creditors think you're going to replace all labor.

Because the people who funded them from the outset did so because that was their goal? The destroy all jobs talk started at least 10 years ago, it many ways that hype is the actual product itself.

Because that was the truth. Now they have learned they are going to have to lie to the people so the masses can be sleepwalked to the same eventuality.

They were being earnest. People can't handle the truth, so now they're doing PR comms.

Class blindness. Their buddies all love the idea of showing pesky workers their place.