Because the idea is so often advanced without evidence by known bad sources.
This article seems more level headed, and indeed acknowledges the problem.
Maybe its most frightening sentence is:
> US Department of Homeland Security (DHS) is currently constructing a new and expanded national Bio and Agro-defense facility in Manhattan, Kansas. DHS has estimated that the 50-year risk (defined as having an economic impact of $9-50 billion) of a release from its lab at 70%.
This article seems more level headed, and indeed acknowledges the problem.
Maybe its most frightening sentence is:
> US Department of Homeland Security (DHS) is currently constructing a new and expanded national Bio and Agro-defense facility in Manhattan, Kansas. DHS has estimated that the 50-year risk (defined as having an economic impact of $9-50 billion) of a release from its lab at 70%.
That's .. not great odds.