I'm pretty sure founders at Buffer feeling real bad about firing folks doesn't make the experience any better for the fired folks. Three to six weeks of severance is a tight turnaround to get a new job, particularly for non-engineering employees or remote employees. And, guessing based on their ramp-up and lifo scheme, they're probably firing some employees inside their first 6 mos. ie they most likely recently left a job for Buffer. I understand there's no promise of lifetime employment, but that's a serious dick move.
You can compare this to big game companies, which have no problem hiring a bunch of people and then laying them off when the project is done. All the disadvantages of being an employee (IP assignment for side projects, low pay) with all the disadvantages of being a contractor (no income stability).
Companies do what they need to in order to survive, but that doesn't mean that the people running the companies are always 100% soul-less