Well, my kids are not spoiled.

So I think we're good. I lived overseas for extended periods myself. It's a complicated question. But on the whole, it seemed to me that people in other countries enjoyed showing Americans around, and they were often eager to share. To say they have nothing is generally an overstatement. In fact, I have found them often to be very generous with me, worrying over a hole in the sleeve of my shirt and whether I had adequate clothing, etc. Vietnamese refugee children made me a lovely scarf and a bead necklace when I taught a class at their camp. It depends a lot on ones attitude toward them. If it is superior and obnoxious, then of course they may feel humiliated. If someone is there eager to learn about their culture and participating with them, then they are often quite flattered.
I'm not saying short term missions don't have problems. They DO have problems. So often that I have said myself that they ought to be stopped. But I've reconsidered that the problems are not always terminal, and when I think of it in a balanced way, I do remember some really obnoxious Americans sailing through, but I also remember some very helpful souls who were much loved by all.
I've endured grinding poverty at certain phases of my life as well, so I'm not insensitive about it. But it's not such a humiliating situation that we all ought to go about with our heads covered to avoid seeing it. They are people first, and often very sweet people, who sometimes like visits and opportunities to share their culture and tell their stories. Offering the same respect as to the members of our own congregation (as you mentioned) is actually an excellent way to do it. And I visit the elderly poor widows in our congregation. They serve me tea and tell me about their lives. It's sweet and I take my children along to learn to minister to others, and I don't think the elderly widows believe I'm there to stare at them.
PS However, that being said, problems do arise in short term missions when people are primarily tourists--staying in missionary homes and making a pretense of 'ministry' just to get a good deal on a vacation. Like I said, there are problems with those missions. But not ALL the time, and not everybody.