Oh, moral relativism! How fun!
The Make-A-Wish Foundation is terrible. It is impossible to defend it by claiming it does a good job. So instead people fall back on "gosh you're mean" and "stop shaming me!" and "everything's like, totally relative, dude..." Seems you've chosen a combination of the second two.
Notice the contradictions in your comment. Effective altruists "value things differently" than you do. They care about efficiency and objectivity. Yet you're criticizing them for it! You can't have it both ways. Either it's wrong to criticize "people who value things differently," in which case it's immoral for you to criticize effective altruists for their values, or it's fine, in which case you have no reason to criticize them.
I've never met a genuine moral relativist (at least as most people use that term). I've met lots of people who claim all values are subjective, but never one who actually acts like it. They'll trot out that argument to escape from a tricky spot, but within five minutes they'll be right back to talking about objective morality.
I, for one, have no real problem with the Make-A-Wish Foundation. It just isn't a charity. It's an expensive luxury brand of peace of mind.