I think other commenters have had a similar idea, but here's one way to say it.

It seems to me that the proposition you are attacking is not exactly the one you think you are attacking. I think you think you are attacking the proposition "charitable donations should be directed to the highest EV use, regardless of the uncertainty around the EV, as long as the EV estimate is unbiased," when the proposition you are really attacking is "the analysis generating some of these very uncertain, but very high EV effect estimates is flawed, and the true EVs are in fact a great deal lower than those people claim."

The question of whether we should always be risk neutral with respect to the number of lives saved by charity is an interesting and difficult one (one that I would be interested to know what Holden thinks about). But this post is not about that difficult philosophical question, but simply about the technical question of whether the EV estimates that various people are basing themselves on are any good.