Are you thinking about this " how on Earth can a sexually transmitted disease research centre have ethical issues?" In fact, there is only one but one that could topple the whole research grant over the edge. The thing that was particular of concern to the Animal welfare group was the utilization of primates, mice and other small creature as experimental subjects to deliver vaccines for the human race. There have been many reported treatments of misconduct, torture and inappropriate application of biological liquids on the animals.
The above images as you can see shows a primate and and row of mice undergoing experiments to see what happens when a particular chemical is injected to its veins. How is this not different in any way to the Jewish Holocaust? That point caused many outrage in the animal welfare groups in America and Europe and sparked many protests to stop the use of primates and mice for scientific research. Although that is not the point which most people are worried about.
Swear at, shot, injected, kicked, stabbed, punched, deformed...all the horrible words you can think of are happening to many primates at many primate research around the world. Particular in America, the case gets worse. There were evidence of unauthorized experiments carried out in secret. Primates not receiving anesthetic prior to surgery and ruthless kicking and punching of primates. The smell of blood and primates screaming dominate the voices of the doctors at the research centres, primates are being tortured with electrical rods and jabbed with needles. In the end, most monkeys were driven mad by the lack of air and movement in their metal cages. Below is an example of the cruel treatment in a research centre in America.