If British Empire is bad then there is no empire that is good. Every empire has history of genocide of some sort.
It is unscientific to judge thing without assessing how it stands on relative-terms.
British Empire certainly has its flaws but its fruits by objective measures certainly outweighs the bad.
The founding of Industrial Revolution and its promotion of global trade and its financial system are certainly good things. For all fairness and purposes, before the ascent of British superpower, yes a number of European powers are already doing inter-continental trade but British helped bring about global trading to a new level. Before 1750, GDP per capita of the world has mostly been stagnant. There are many factors that contributed to the meteoric rise of economic growth for the past 250 years. British Empire plays an important role in the creation of a global system that promotes growth. It also implanted civil administration system in its colonies. Prosperous economies like United States, Hong Kong and Singapore are off-springs of the British Empire.
If you are against industrialisation, if you are against economic-growth, if you are against rationalism then you would probably think British Empire is bad.
But if scientific progress and economic progress are not important metric of what is good and what is bad, then there is absolutely nothing to measure how we should measure progress. Life would be so meaningless in the views of these nihilist. Frankly, I think the world is better without nihilist thinking. Mankind need a sense of direction of how human existence and energies should be directed and nothing would be better than the expansion of economic and scientific level.
Mankind can land on the moon, can use the internet and has access to countless modern-necessities because of the belief of economic and scientific progress. Here is a thought, economic and scientific progress do make humans survive better. Humans can survive random natural events better with better economic and scientific condition. Heck, even 50 years ago mankind has zero-chance to survive a meteor-armageddon scenario that wiped out the Dinosaurs 65 million years ago. Right now, we probably have some chance to survive with the ability to nuke the meteor.