Your right...if our liver's were working as they should, our immune systems would be working better etc...
One of the things with parasites, especially if they are able to take over when the body is weakened--which is what they do...is that they further deplete the body because of robbing our nutrients from us- I think it's Tapeworm that depletes us of B-12...plus that, they have their own viruses/bacterias and toxins they put off--which is not a pleasant thought.
Have you noticed how many of the people that are on CZ, are (on the average) in their 40's-50's? Young..yet with health problems that most people will start to recognize, in looking back, have been going on for years.