Earlier quoted context omitted.
It's not the lawsuit, it's about the time wasted as a manager and salary to the person as you work out if it's actually time to fire. Performance Improvement Plans, a bunch of back-and-forths. I'm not going to be the kind of person that fires quickly, so there's a bunch of sunk cost we have to take. Plus, fast firing creates a cooling effect among everyone there. And for what? To save money on hiring? Not worth it.
The counter argument is that firing too slowly can be a serious drag on morale. Leaving your team to carry dead weight can really suck for the team. Ask me how I know... :)
I mean, being a manager is hard, but putting in the time and money to hire and then putting in the time to make sure your team doesn't have a morale drag, it's worth it.