This is not at all unusual in cases like this where large layoffs are involved, in fact it's standard operating procedure. Yes, it may appear shabby, insensitive and cruel but it's done as much for the safety and security of the recently departed as it is for the company as well as to keep the disruption and distraction to a minimum inside the building. At the end of the day, it won't matter how it was handled, as in a few short hours, the morale of the staff left behind will suck big time!
What's more important is that those layed off were treated fairly and respectfully with severence packages. I don't know the employment standards laws in Wisconsin, but local laws notwithstanding, the rule of thumb for "good" companies is one month for every year of service. This is prudently done to avoid or minimize the spectre of far more costly wrongful dismissal lawsuits.
As someone who has personally witnessed a large layoff and been the victim of another, one observation has remained: For whom is this devastating event worse for, the ones let go or the ones left behind?