Because it's a layoff. Even when done right, when the company lays off people in the bottom 25%, there's still just as much work and fewer hands to do it; If you aren't cut in the first round of layoffs, you will end up working much harder than you were working before the layoffs.

Usually, layoffs also imply that the company is in poor financial health. Companies in poor financial health tend to be stingy with raises and bonuses.

I would argue that because they are doing layoffs wrong, they are very likely going to endure even worse times; It implies they have unskilled management, and they've got to get along now without the employees who had other options who were encouraged (!) to jump ship before things got really bad.

Few things are quite as frustrating as putting in heroic hours only to watch that work be wasted because your management isn't very good.

If you thought you had to work more after the first round of layoffs, boy howdy; after round two, you might as well park your cot in the office. Worse, in round 2 and 3 the severance packages get smaller and smaller.