"In 1998 a case involving Jehovah’s Witnesses in Bulgariawas given attention by the European Court of Human Rights. What led up to it? The Bulgarian government had deprived Jehovah’s Witnesses, as well as some 20 other religious groups, of legal recognition. An appeal to the Bulgarian Supreme Court had been denied because, among other things, Jehovah’s Witnesses do not believe in the Trinity and in other non-Biblical doctrines of Christendom. This led to arrests, the breaking up of meetings for worship, and the confiscation of religious literature. The European Court urged Bulgaria to settle matters with Jehovah’s Witnesses on a friendly basis. As a result, in October 1998, Bulgaria again gave legal recognition to Jehovah’s Witnesses. This made it possible to send four missionaries from the 106th class of Gilead to Bulgaria to assist the local publishers in sharing the Kingdom good news with the people there." (Yearbook of Jehovah's Witnesses 2000, p. 24)
This leads to the impression, JW were somehow persecuted because they rejected the Trinity. The blood issue was just included into "other things".