What can be said about the moral principles of the British colonialists who used the opium trade as a means of subjugating China?

What can be said about the moral principles of the British colonialists who used the opium trade as a means of subjugating China? Could such a trade become a pretext for a war between European countries?

The Chinese empire at that time had a traditional Confucian view of merchants and commercial activities, which was fundamentally at odds with the British course of free trade. Many early European explorers played down the importance of opium as a cause for war. After all, the economy and culture of the conflicting parties and without it were on the edge of contradiction. They tried to find a moral justification for the war, secretly advocating for the illegal but profitable drug trade.
Today historians are focusing more on mercantile logic and warfare because drugs have provided Britain with a unique opportunity to patch holes in the country’s financial resources. And the notorious “clash of civilizations” plays almost no role here. In light of Britain’s dependence on Chinese exports (silk, pottery and tea), opium was the only commodity that helped keep Britain in balance in its financial relations with Asia.