Guantanamo - is force feeding an assault?

President Obama said in 2006 that he would close Guantanamo but it remains open. Many of the prisoners are now on hunger strike and are being force fed. It is my understanding that (at least in the UK) unless a person is declared severely mentally ill and unable to make rational decisions, force feeding that person constitutes an assault.

Does the existence of Guantanamo shame America and its close allies?