Along with the externalities of much less of your money actually going to the charity, and of being regularly solicited/harassed on the street by the same people wearing whatever vest related to the charity they're promoting on that day; they're akin to popup ads that everyone despised.

Yes, if the charity is geting 2x the spending with the fundraiser, that means the fundraiser is getting 1/3 of the funds. Pretty gross, IMHO, but if the charity needs (or can reasonably use) 2x the funds, it's kind of hard to argue against the results.

I disagree. First, because there's some evidence that most people will give a fixed amount to charity (I'm too lazy to find a source), so they're playing a zero-sum game and any fundraising overhead just takes away from money being given to people who need it.

Second, because that money doesn't come from a vaccuum. People who spent it on charitable causes could have spent it on other things; some of these things might be a new smartphone or fancy food; but some of them might have been an electric car or a college fund or whatever.

So super-expensive fundraising takes money away from other parts of society, some of which might be productive, to sink it into the giant resource-wasting game that it advertising.

Personally speaking, I donate to the Global Fund. They do relatively little advertising, but they get shit done.

I have heard it is 50%+ that the fundraiser keeps.