I agree with the stance you have, and it is somewhat of a thorny issue. Swans being removed means more predation upon native species and their eggs by rats, foxes, cats etc. It is one of those questions, now that the environment has been changed, do we attempt to remodify to try and regain natural, or do we acknowledge too much, too soon and manage what has been created?
It is truly a tough question, I hope that whatever is done, if anything will help and not hurt.