I don't think that's what the parent was saying. They are saying the Nazis are truly evil, but the Brits are also truly evil. A different truly evil, of course, I'm not going to weigh tragedies against one another.

And they're not wrong. The British empire killed millions through policy -- read up on the Bengali famine to understand one example where Britain killed millions. Britain was one of the earliest users of concentration camps, deploying them during the Boer War.