As a "non American" I saw Louis Theroux's documentary on the Phelps. I found it quite appalling.

As an example this is an extract from the Irish Constitution

Article 40.6.1°, paragraph i of the Constitution provides that, subject to public order and morality, the State guarantees liberty for the exercise of- The right of the citizens to express freely their convictions and opinions. The education of public opinion being, however, a matter of such grave import to the common good, the State shall endeavour to ensure that organs of public opinion, such as the radio, the press, the cinema, while preserving their rightful liberty of expression, including criticism of Government policy, shall not be used to undermine public order or morality or the authority of the State. The publication or utterance of blasphemous, seditious, or indecent matter is an offence which shall be punishable in accordance with law.

I think the problem in America arises with the fact that "Freedom of Speech" in the constitution seems to be unqualified.

The Irish Constitution guarantees your right in Ireland to freely express your convictions and opinions. However, it also asserts that the state should try to make sure that the radio, the press and the cinema are not used to undermine public order or morality or the authority of the state.

The Constitution also states that it is an offence to publish or utter blasphemous, seditious or indecent matter.

The full text of the Irish Constitution is linked for those interested. Article 40 is the relevant article.