There is a slight difference. The Brits were fighting a war against the Boers. Stalin and Hitler did it to their own people. I also think the Brits had the idea but really didn’t think it through, and weren’t prepared to properly care for so many prisoners. It was more of a crime of ineptness and omission rather than a cold-blooded desire to kill the undesirables.
The Brits knew exactly what they were doing. They were told numerous times and did nothing to improve the camps - in fact the situation rapidly deteriorated.
As it was 29,000 women and children died (1 in 4). Had the Boer armies held out another year or 2, very few women and children (if any) would have survived.
The Brits (then) were every bit the rat bastards the German Nazis and Soviets were..
So the Ruskies weren't 1st as the article suggests. Let's give credit where credit is due and pin 1st prize on the Brits.