Bezos decided to hire them part time, so the question is kind of ludicrous.

How is it ludicrous? They are counting part-time workers among the "benefits" total which is disingenuous and not apples to apples at all.

I think the point is he could just offer full-time jobs instead.

There's nothing to say that people were offered full-time work and opted for part-time instead. Regardless of employee preference, it's still not apples to apples if trying to make a comparison to income qualifying for government benefits.

Is a business owner that only requires part-time work supposed to hire full-time workers for some arbitrary reason all of a sudden?