Other than that the US kidnaps people from various countries, often without approval of the country where the kidnapping happens, brings the rebel (patriot?) to Guantanamo Bay without even trial by US legal system and waterboards and tortures them and holds them indefinitely - although some are realized to be the wrong identity and let go - there is another point...
...Cuba has denounced the US military occupation of Guantanamo Bay for decades, and requested the US to leave. So this is happening against the wishes of the country it is happening in.