Manchu conquest, helpful or harmful?

Han Chinese have two answers opposite to each other.

1.

Han Chinese have been blaming Wu Sangui the traitor ( though Li zicheng is the real traitor). —- It seems Han Chinese think Manchu conquest is harmful. Or else, there would be no traitors, nor can they have any reason to blame so called traitors.

2.

Han Chinese are happy to see their territory being expanded to the unprecedentedly extend. —- It seems Han Chinese think Manchu conquest is helpful. (They even proudly claim that their country was the largest in the world in their Yuan dynasty.)

Han Chinese have also been thanking Manchu for their good emperors and their good rule. —- It seems Han Chinese think the Manchu conquest is helpful.

But how can the same thing be helpful and harmful to the same object?

Manchu conquest, helpful or harmful?

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And why did Han Chinese get conquered?

Han Chinese also have their “diverse” reasons,

We the great, superior, civilized ethnic group got conquered by Manchu?

• It is because of Wu Sangui the traitor.
• It is because Manchu were beasts, uncivilized, barbarian, cruel, war-liking.
• It is because we pardoned Manchu.
• It is because Manchu emperors and Manchu rule were good to Han Chinese.
• It is because Manchu and Han Chinese were brothers/sisters.
• It is because we were unwilling to kill them.