I don't think we can hide the past behind "hindsight" all the time. At least some horrors from history it's fairly obvious that even the perpetrators knew what they were doing was wrong, but carried on anyway. One can see this, for example, whenever a cover-up was involved -- as a rule, people don't cover up their actions if they don't think they need to be hidden.
The British Empire perhaps gets too much stick but most of it is justified -- as long as it's placed in context. First one is that it wasn't the only Empire at this sort of crap -- Spanish, French, Dutch, Portuguese... well, European in general. Not to mention various local empires or civilisations. In general they are all as bad as each other. I think some people twist this to justify the British Empire's actions as either typical of the time or somehow not really as bad, but this is just the "well, he started it!" playground bullying excuse. It doesn't work there; it shouldn't here. And anyway, we did end up being the largest Empire the world's ever seen so, unsurprisingly, probably ended up with the most such deplorable actions overall, at the time at least.
None of this means that the British Empire was a "bad thing". Equally, the various atrocities we did commit surely ought to sway anyone from thinking of the Empire as intrinsically a "good thing". Perhaps the Empire was good for countries, but it was fairly awful for their people. People don't, as a rule, like being invaded by force of arms by a foreign force and then ruled with no say whatsoever over the laws consequently imposed (sound familiar?).
There appears to be a mentality among some that Britain was the best thing that happened to the world. I'm not sure the world always agrees. Perhaps it was, though, among the "least awful".