Why do you quote only the end, the full sentence is: We cannot discard, for example, than an ant has a greater qualia level than

They're saying that since we don't know how to "measure consciousness" we can't be certain that an ant doesn't have more "consciousness" than us. Obviously it seems very unlikely, but we can't be certain

I don't share that interpretation, maybe they clarify what was meant themselves?

fwiw i share the same interpretation as the other commenter.