It’s because they do stupid stuff like taking a strain of the Wuflu that kills almost no one and turning it into one that could kill 80% of those who contract it. I will note that this was done in a lab with the most stringent protocols, but we’re all fallible humans-we make mistakes. I’ll leave it as an exercise to the reader just how serious a mistake in this situation could be. Think The Stand.
You’ll probably miss how incensed he is if you’ve never been around educated Englishmen. But trust me, the man is pissed beyond belief.