"Your way of helping others isn't good enough."
That seems like a condensed version of your argument, which I would say only holds water if 100% of your money beyond what is necessary to meet your basic needs goes to charity. Otherwise, it comes across as a bit hypocritical to me.
I definitely get your point, and it was my first thought too. HOWEVER, I also try really really hard to learn things that I don't know.
We've never done any kind of foreign volunteer work, and I only know 1 or 2 unskilled people who have done this. (But many skilled people like nurses.) So, I don't have a dog in this race.
It never would have occurred to me that these could be actually harmful, until I read the link posted here and did some more reading.
Just like, a lot of people fly for vacations all the time and never consider the climate implications - (I mean, some do, and they do other things to offset their climate effects, cut back on travel, etc. etc. - it's a spectrum), and some people don't think about the effects of sending money/ aid to Africa, etc. (Because, well, you don't know what you don't know...there are lots of things that I don't know, and unless I read books and stuff about it...I never will.)