Telling another poster that something they have said "is absurd" isn't very tactful or sensitive to the other person's feelings. It also conveys a sense that you have great knowledge when in fact there is no reason to assume that you know everything. Liver flukes, like all living things, need a place to live. It seems possible to me that if they have a nice "nest" they may grow big and sstrong more than if they don't. If you disagree, again, you don't have to say someone else's comment was "absurd" and you don't have to assume that everyone else should assume that you are a big time expert.
We all have our opinions and perspectives. The idea is to share, not to put down anyone else.