Jokes aside, this is a thought provoking quote. I do think it's easy to say as a well known figurehead, when the quote and other actions below you may easily be attributed to you, at least partially. But I do agree somewhat, and I think the context around Truman's time (WWII) is a good example of what humanity can accomplish when the stakes at hand supersede the considerations of workers' rights or credit/ownership. Of course this is also a very favorable phrasing for a period of enormous human suffering. I think there is an arms race analogy to be drawn here, though the current situation and stakes are much different.

'A man may do an immense deal of good, if he does not care who gets the credit for it.'

"QI hypothesizes that a Jesuit Priest named Father Strickland deserves primary credit for this family of sayings. This claim is based on the diary entry dated September 21, 1863 written by Sir Mountstuart E. Grant Duff and multiple attributions thereafter. However, similar maxims may have been developed independently."

[0] https://quoteinvestigator.com/2010/12/21/doing-good-selfless

--Albert Einstein (Director, Los Alamos Laboratory)

For example, one generally don’t name cells in their body, and cells works generally pretty well to sustain a whole self.

On societal level, obviously no one is aware of who authored the biggest mass of benefit that is granted by the mere fact of living in society. No specific individual have credits for example regarding the language they use daily¹. For the most recent ones, it’s now often possible to attach some name to invention of some cultural/technological artifact, but of course Zeitgeist-wise perspective tend to consider it’s rarely a single punctual individual that should be considered the critical pivot point.

On the other hand, even Marx that was so critical of individual alienation couldn’t refrain to make the intellectual equivalent of pissing territory and attach a name referring to its own ego within all of his works. Ego is a masterpiece of illusion: it will bring the foundational leveraging to build every possible societal hegemony under the sun while convincing the deluded that serving the ego is the indispensable first step of everything to best serve every individual selfs.

¹ Even for constructed languages, such as Esperanto that I practice myself, whoever construct them obviously don’t start from cultural blank slate.