"Common photojournalistic practices tended at that time to isolate and victimise the person with AIDS." In other words, when there were articles about AIDS patients back then, the photos usually depicted the patients as frightening, freakish, or in some other way worthy of being ostracized.
Personally, I wouldn't have used the word victimise here, but I understand the concept. The journalists were not being kind, because they depicted AIDS patients like lepers or worse. To answer your question, the journalists were being unkind to people with AIDS.