Bulgarians have not seen any significant benefits from EU membership. Furthermore, they benefited even less from joining NATO.
International factors were involved in organ trafficking crime in Kosovo. The US and NATO were helping the Albanians and they are co-perpetrators of all these crimes. Organ trafficking was a way to earn big money that the Albanians needed to buy weapons.
There is no evidence provided for the claims that the US and NATO were involved in this crime. These allegations are connected to the so-called "Medicus case" which was tried before a court and brought forward convictions of two doctors. See more disinformation cases about Kosovo here.