Why do you think the Boxers murdered missionaries and attacked foreign legations?

The Boxer rebellion was a violent movement against Christian missionaries and foreigners in China between 1899 and 1901, near the end of the Qing dynasty. Extreme weather conditions, Western attempts at colonizing China and anti-imperialist sentiments in the Chinese were some of the causes. A major cause was missionary activity. The Treaty of Tientsin (or Tianjin) and the Convention of Peking, signed in 1860 after the Second Opium War, had allowed foreign missionaries to preach anywhere in China and buy land to build churches on.