When you see the return on money spent this way other forms of aid start looking like gatekeeping and rent-seeking.
That said I also think that longer term research and investment in things like infrastructure matters too and can't easily be measured as an RCT. GiveWell style giving is great and it's awesome that the evidence is so strong (and it's most of my charitable giving), but that doesn't mean other charities with less easily researched goals are bad necessarily.
As the numbers get larger, it becomes easier and easier to suggest that the organization's continued existence is still a net positive as you waste more and more on the organization bloating.
It's also surprisingly hard to avoid - consider how the ACA required that 85% of premiums go to care, and how that meant that the incentives became for the prices to become enormous.
To be fair, that particular example was obvious from day 1.
But it's an excellent example of how something you could see some naive people in good faith claiming is a good thing can be pathologized.