Here is one web page on the website that shows how the innocent are trampled in the Roman Catholic Church's quest for power and money. The article begins:
The Polish Government can afford to subsidise Church influence in every corner of society, from chaplains throughout the civil service to holiday pay for the monks and nuns who teach religion in state schools. Yet it is unable to provide free school lunches for Polish children, a quarter of whom are malnourished. This is an itemised list of state subventions to the Church for 2008.
Here is a FAQ page that gives some basic questions and answers about concordats. Following is one quote from the page about what a concordat is:
It's a commitment to give the Church certain legal and financial privileges forever, unless the Church agrees to relinquish them. You can change a law if enough representatives vote to do so, but you cannot change a concordat without agreement from the Vatican, because it is classed as an international treaty. Once in place, therefore, concordats are removed from democratic control.
The basic premise of the website is that these 'concordats', which are sometimes called by other names to disguise what they are, are a danger to the civil rights of the citizens of the countries where they are enacted. Concordat Watch calls for true separation of church and state. I want to clarify that there is a true concept of separation, which our founding fathers endorsed; and there is a false concept of separation which today's liberals call for. The false concept is that there can be now mention, symbol, prayer, etc. of Christianity in or related to any state-run property or organization. They don't seem to care if other religions are represented; only Christianity, especially Biblical Christianity, is abhorred.
The true concept of separation of church and state is that the state shall make no law that inhibits the free practice of religion, and that no church shall control the government and so inhibit the civil rights and free practice of religion for the citizens. Thus, there is a wall of separation between church and state, but not so that no mention of God is allowed on state property, for example.
Here is another section from the FAQS page about how the concordat effects the citizens:
What powers are conferred on the Vatican and what liberties do citizens of concordat nations sacrifice, if any?
It varies from country to country, because concordats demand whatever the Vatican thinks the market will bear. Current concordats in countries like Poland and the Dominican Republic forbid anyone married in a Catholic Church to ever sue for a civil divorce. The Polish concordat phrases it with great delicacy (1993, Article 10.2), calling for the state to put in place the enabling legislation which would enforce "concordat marriage". But the Dominican one (1954, Article 15.2) is franker: "by virtue of contracting Catholic marriage, spouses renounce the possibility of divorce, which shall not be applicable to these Canon marriages". Here we see how a concordat can deny some citizens their rights under civil law in a direct fashion.
Generally, however, this is done in a more roundabout way. The concordat grants taxpayers’ money to Catholic social services (for example in Germany Catholic hospitals are funded to 98.2% by the state) yet it also stipulates that Church institutions are to be run according to Canon (Church) Law, and not civil law. This means that if you work at a Catholic school, hospital, care home, etc., you can be fired for changing your religion, being gay, living with a partner, or even remarrying. Thus you can be denied your rights under civil law indirectly, that is, if you want to retain your job.
Furthermore, with such generous state subsidies there are many places in, for example, Germany, where Catholic social services are the major or even sole employer in some field. This can result in people feeling they must go to church and even force their families to attend, in order to have a chance to get a job. It’s this unofficial erosion of liberty which is the most worrying thing. No concordat is going to come right out and say: “You must give money to the Church if you want to make sure that someday your handicapped child gets a place in a Church-run (yet state-subsidised) sheltered workshop.” But the concordat sets things up so that this can happen.
My conclusion:
Is the church meant to be a political state that makes agreements that enable it to entwine itself into the workings of governments in order to gain power over the citizens and money for its own purposes, to the detriment of the weakest members of society? OR is the church meant to be the body of Christ that appears in local bodies all over the world and which live to love God, love each other, love their neighbors, and make disciples of all nations, teaching them to obey the commands of Christ; not by compulsion and power of a hierarchy, but by the word of God worked out in love by each member.