My experience with underperforming workers is that often it is directly the result of poor management. I’ve seen entire teams underperform because of some arbitrary decision from a director. Changing priorities at times when it was guaranteed to remove momentum, or worse, destroy moral. I’ve seen individuals underperform as their manager interrupts them at a concentration destroying cadence. Hell, just 2 well placed meetings can completely ruin a developer’s productivity for an entire day. And then there’s environmental problems. I sat in a cube where the accoustics were such that one particular cube far away sounded like the person was in my cube. I tell you that was hard to ignore. I also once sat somewhere where sales constantly was walking past me. That led to many frustrated hours, and if they didn’t work 2 hours earlier than me, so I could start getting things done at 3pm I don’t know I could have done anything in that job.

So maybe firing someone for underperforming is abusive?