You obviously care a great deal about the sufferings you've indicated, and I wish you luck in finding the most constructive way to gain useful attention to them given all the info we get from various sources and the endless options for people's attention and concern.

However, in my experience, when people say that historical figures can't be judged by present standards, they're referring more to acts that today would be considered politically incorrect rather than objectively evil, and it might be beneficial for anyone to ask if they could ever confuse one with the other. To take a popular culture example, the Little Rasals/Our Gang short movies of the 1930s would be inconceivable to produce today, but given what their makers had been exposed to they appear to have made a distinct effort to portray the black children well.

Perhaps it would be easier to consider non-racial examples, such as the type--or, at the risk of being more pejorative--quality of the humor of 1970s sitcoms compared to modern ones. Setting aside examples involving minorities (for this purpose) and just focusing on the writing styles, you might find one in general to be quite better or worse than the other, depending on what tone you're in the mood for.