We aren’t much into theories denying the moon landing around here, but [Dagomar Degroot], an associate professor at Georgetown University, asserts that the Apollo 11 quarantine efforts were bogus. Realistically, we think today that the chance of infection from the moon, of all places, is low. So claiming it was successful is like paying for a service that prevents elephants from falling through your chimney. Sure, it worked — there hasn’t been a single elephant!
According to [Degroot], the priority was to protect the astronauts and the mission, and most of the engineering money and effort went towards that risk reduction. The — admittedly low — danger of some alien plague wiping out life on Earth wasn’t given the same priority.
We honestly don’t find that very surprising. First, only on Star Trek and similar works of fiction is alien life so compatible with ours. We strongly suspect that alien life, when we find it, won’t really like the taste of us and vice versa. Besides that, even with what we have learned recently about the hardiness of life on Earth, the idea that life exists on the Moon seems pretty farfetched. We suspect people understood that in the 1960s, too, and simply went through the motions to quell fears from anxious bosses, politicos, and the general public.