I have never volunteered internationally, but even setting the racial component aside, here, I think this is spot on. I supervised volunteers helping to rebuild in a Katrina-devastated New Orleans, and volunteerism is often about the volunteer having an experience and growing as a person, and not enough about the work that needs to be done. How much time I wasted on useless people - teaching them, re-doing their work, finishing their work after they quit to go to a prayer meeting or have a little me-time.
The intentions are pure, mostly, but the effort is misguided. You might say, we should be grateful for what help we got. But we were grateful for the useful help we got. We were grateful for money to hire skilled locals. Not to mention, these high school and college-aged kids were putting something on a college application or resume - or checking off a box to get into heaven, clearly amazed that we were not holding ceremonies to thank them for their fearless effort. We were not thanking god for them.
The linked article brings race into it; I am sure we all can envision the white savior mentality at work here. I certainly had white savior ideas in my head, when I was a young dipshit. White people in this situation always think they belong, and they always think they should be given credit for common decency toward those not like them. Credit for braving a world tons of people live in, credit for associating with people less privileged.
The other problem with voluntourism is that those who tour, view the people they are there to help as some sort of zoo animals. If I had a dime for all the times I listened to group leaders talk about how the volunteers are there to benefit from being exposed to other cultures - I agree on a broad scale, in concept, but not in a short-term, gawk at these poor people and then return to your life and reflect upon how the mere fact not everyone is like you has changed your life!
I was a voluntourist, but I was committed for a long term - 3 years. In that time, I quickly saw the damage done by volunteers-who-do-not-belong. I hope I changed quickly. I became protective of the community I was living and working in - and the people who were community leaders from long before the storm. I can only imagine the inane, naive, stupid shit I probably said and did, and like every good voluntourist, I had a long journey of self-reflection and becoming a better person. Did I belong? Maybe not. My expertise and education were used but there were probably locals with similar qualifications. Who knows?
You probably cannot build a house: do not volunteer to do so, thinking that your small contribution will still help. Do something you can do, or give money to someone who can.