Fearless Hollywood

I agree totally; this film truly stands out in that it avoids simple-minded characterizations. While Robert Wise and others may have intended the movie to have an anti-imperialist or anti-jingoist message, I see "Sand Pebbles" as a story of very different types of westerners all finding themselves outmoded in a foreign land torn apart by brutal internal strife. Yes, there certainly seems to be a preachiness in this film, and indeed I know some scholars want to see this film as having an anti-colonialist or anti-nationlistic perspective, based mainly on the statements of the patronizing Jameson. However, in my view the film makes brutally clear that Jameson's belief that adopting a politically neutral stance in the conflict and having a piece of paper to back it up can somehow wipe away his national or ethnic identity and thereby protect him from the violence around him "Damn your flag" is just as foolhardy and destructive to himself and those around him as the Captain's pursuit of glory and honor "If the San Pablo dies, she dies clean".
Keep in mind, just as in the Boxer Rebellion twenty years before, westerners, including missionaries(as stated in the film) were slaughtered by bandits and soldiers alike during the Chinese Civil War. In the end, Collins' actions(taking the San Pablo to China Light)are far more pragmatic and appropriate than Jameson's, which fail to acknowledge the seriousness of the situation, and probably would have gotten his young ward raped and killed. Indeed one could argue, that Collins' pondering of suicide is not motivated by a sense of failure, but rather by the contemplation of the far sadder fate of becoming useless in the face of an increasingly ambigious conflict. Only the clarity of the missionaries peril gives him (and the San Pablo)a renewed purpose.
While Collins and Jamesons' beliefs represent some of the larger idelogical struggles of westerners caught up in the conflict, Frenchy's romantic passion and Holman's rebellious nihilism "I have no more enemies" are much more personal but equally destructive. And while all the lead characters in the film are shown to be brave and intelligent people that transcend simple stereotypes, they ultimatly retreat back upon their more deeply held ideals when the world around them collapses deeper into savage partisan violence and chaos. In the end it is the more pragmatic, or naive, people that survive the bloodshed. As other posters have pointed out this film also shows both the good and bad of China during this time a well; and in the end, while there is certainly some sympathy with the Chinese people shown, one cannot help but view the whole struggle as a sensless bloodbath. As I said above, I can't speak to Mr. Wise's intent, but it seems to me that this film, like my other all time favorite, "The Man Who Would Be King", is less about preaching a particular political meesage and more about showing that when people are motivated blindly by strongly held beliefs, whether personal, religious, social or political, they often are unable to adapt to situations that do not neatly fit into their particular worldviews.