Earlier quoted context omitted.
What's less cruel? Face to face meetings? Layoffs suck, how is this particularly egregious?
Seriously, if you cannot see that "fire by email" is far more impersonal and disconnecting than compassionately meeting with the employee 1 on 1 and giving them a definitive exit path along with the financial support to do so, then please do not ever work in HR or be responsible for employing people in the future. To subject ALL your employees to the 50/50 prospect that they will have a job come next working day is t…
On top of that, there are security concerns with hanging onto employees and letting them have access to company property during a time that they know they will be fired. Especially for a company that performs services for top secret government projects.
The easiest (though you won't catch me arguing that it's the best) way is to hold a staff meeting, and then let corp IT churn through the 6000 person list over the weekend and remove access.