When the first tainted was created there were riots in the streets, shortly thereafter the Dragano Alliance was formed by many of the nations that were originally part of NATO and then many of the countries worldwide began to follow in suit. One country in western Europe called Artinia began kidnapping gifted children from neighboring nations that were trying to be a part of the Dragano Alliance. Artinia then began making thousands of their military tainted using the gifted children. In response, the Alliance declared war on the country. Every single one of the children that were kidnapped to make their soldiers tainted were killed in the process, and the stigma against the tainted was enhanced. The War was eventually called the Tainted War, and it lasted almost 11 years and 25 million were killed, 6 million from Artinia, and 19 million from the Dragano Alliance. After the war the Dragono Alliance could not find the secret to creating tainted in order to destroy it. But millions of tainted began to appear around the world. Many others try to copy this experiment, unsuccessfully, leading to millions of deaths of both from the gifted and the potential tainted furthering the stigma against the tainted. This created a global human trafficking ring of gifted and the ungifted. Not every tainted became a villain and not every tainted was a willful subject in the experimentation, but many of those who chose to become tainted became criminals, and this was a vast majority of the people who were experimented on and this cemented the reputation of the tainted.
This is just a brief history of the tainted, we are kind of retconning the timeline but this is to add more depth to the tainted and to the overall world.