This is a fascinating question. It's incredibly rhetorical, and I've sat here pondering it for a bit. It's very easy to reply to this question with "well I suppose it depends." And then tack on "What do we consider 'doing good/more good'? What is the nature/species/alignment of the lives being saved, and how are are they equal? Who decides which two lives are better to save than the one, if it's somehow decided that one is better than two? Does the two lives vs one life involve picking between the same two lives, or is it an entirely different set of lives?" and a whole mountain of other questions. It's like asking a magical wish granter to "save two lives" and it does something predictably spiteful like saving two single celled organisms and causing a kitten to die. Thanks for giving me that to chew on.

No, quite frequently there are two lives less valuable than one. This is true on the many dimensions you can “measure” the value of lives.

Future potential (“women and children first”), societal compliance (criminals vs not), etc.

What you think is objectively better with something as open ended as $300m is completely subjective.

Considering the infrastructure deficiencies, I think a canning facility would have been better.

Well, how do you count?

One glaring obvious problem with the EA people, is that they double count.

Say I give money for bed nets, and the bed nets save 100 lives.

But say I only gave that money because Eliezer Yudkowsky convinced me to. Was it really him that saved 100 lives? Or do we divide them between us somehow? How many should go to the people who actually distributed the bed nets I paid for?

You'd think the EA people would have good answers to these questions. Or at least, any answers. But they don't. Not any consistent ones. They cheerfully double-count in all their most famous arguments.