I have to disagree with you. We do worry about chicken contaminated with salmonella, and certainly the people who get sick do worry about it.
One of the major differences in laboratory environments versus level 2 organisms in the environment is that you take those level 2 organisms, you grow them, you concentrate them, so you have many more organisms per volume. You would also engage in laboratory practices where, for instance, you aerosolize those materials so they become an inhalation hazard. You do all those things in the laboratory environment that you would usually not do at home when you have those materials.
Does that answer your question?