Having a bad boss who won't let you proofread his presentations is one of the most delicious feelings. Every meeting is like Christmas morning, where there's a good chance you'll get you wish and he'll make the fatal mistake.
A speech like that would motivate the most light-hearted optimist right the nearest window. Dilbert shouldn't think of it as potentially losing his job. He should consider it a chance to help his fellow workers by creating a promotional opportunity.