The demands of those missionaries were shockingly abusive and included land. Mark Twain documented it quite well. And the Germans were among the worst.
Dress it up however you want, beginning with the Opium wars where the Brits forced China to allow British dope in, there was a land rush where western powers invaded and carved up “spheres of influence”. They demanded subservience to their missionaries, and every offense was met with demands for silver and land or another port.
The Boxers were doing what anyone does to an invader.
And the effects of it ripple down to this day where we have a virulently anti-western China to deal with. Of all the abuses in China of that era, the Opium wars and the Germans were by far the worst.
For the Chinese people, as opposed to the Manchu Qing state, it was considerably more complicated than that. Shanghai had maybe a quarter million people in 1842. The foreign concessions in Shanghai (the “international” one run by the British and the Americans, and the French one) introduced the Chinese people there and soon throughout the nation to new technologies, new business techniques, new ideas (individual rights, women’s rights to participate in society in particular, Darwinian evolution, the scientific method, the idea that societies could be dynamic and didn’t have to be mindlessly wedded to tradition, private civic activism and many others). While some of the other foreign concessions did not amount to much and were governed cruelly, millions of people poured into Shanghai to work and to escape events like the Taiping Rebellion. (This tradition continued through World War II, when even under Japanese occupation thousands of Jewish people found refuge from Hitler there.) Certainly outside the concessions and to a substantial extent within them, this Shanghai was the freest place the Chinese had known in their two millennia of history. The British, French and Americans often (though not always, especially in the case of the Christian missionaries) looked at Chinese as inferior, and Chinese had no representation in governance in the concessions at all until the late 1920s, but the foreigners let them build their own lives, without molestation. Which they did once their energies were unleashed, economically and culturally.
Before Chiang Kai-Shek’s unification of most of the nation under his increasingly socialist (a poisonous idea that unfortunately also came from abroad) and nationalist party in 1927, Shanghai led the Chinese transformation toward modernity. So vibrant was it that even KMT corruption couldn’t completely stop the process. That Chinese people poured into Shanghai, and that both the foreign powers (vastly outnumbered by Chinese by about 1910 even in their own concessions) and the locals whose parents probably were migrants themselves accepted this with such equanimity allowed them to continue to build Shanghai as a cosmopolitan, ever-more modern city. That this was destroyed by the Japanese after 1937, the KMT between 1945 and 1949 and the CCP from then on meant that a chance to become the kind of place Taiwan, Singapore and South Korea became after the war was lost for decades.