Why doesn't someone make a group victims fund that evenly distributes to approved families? That way contributions will be tax deductible per IRS.
There have been funds established like that. (That's besides for the funds that have always been around to support almanos, yesomim, and needy people.) They didn't make as much as these campaigns. People that know the niftar donate more and solicit more than they would for a mass fund. In addition, even strangers give more (collectively for sure- most person would faster give $20 to 6 funds than $100 to one). People connect to individual stories more, both due to tendency to live knowing what money is going for and human emotional makeup. One death is a tragedy, a million deaths is a statistic is a fact of human nature that affects us all.
Most of these larger funds are verified causes that are being run through rabbanim. Any donor can get a tax receipt if they want.
The reality is that most people donating $20 or $50 are not itemizing anyways.