If you rule out any toxin exposure, the germ spread of disease is still a theory

In fact, I should correct myself - it is not even a theory, it is merely a hypothesis

To upgrade to a theory you would need to present (or generate anew) some body of experimental evidence supporting it

I don't claim to know the specific cause of every illness
I just know that many experiments have disproven the germ hypothesis (eg Koch's own cholera experiments)