So let’s fix both, not neither.

I'm not sure who you're arguing with, but it isn't me. You said you didn't understand the comment, yet it's pretty much a statement of fact.

I would personally characterize diarrheal diseases as a plague, but I think the broader point is fair: people have lost all perspective on how Covid compares to other causes of death around the world. How far would the tens of trillions of dollars the worlds' advanced economies have spent on Covid in 2020 have gone to eradicating childhood deaths due to dirty water?

You can't simply say "let's do both", because the fact is that we immediately found the money for one, and we haven't found it for the other despite years of effort. It speaks to our priorities.

I understood their dismissal of covid-19 just fine. I don’t understand why people are still stringing that harp a year into this. I would like to believe we have the ability and will to tackle big problems. The existence of another problem isn’t a compelling reason to not act to me.

> I don’t understand why people are still stringing that harp a year into this.

Because it isn't a "harp". It isn't just a niggling little thing, and it isn't "dismissal" to put something into perspective.

The world's economies have thrown tens of trillions of dollars into the response to Covid (not to mention the incalculable follow-on costs in terms of mental health, missed diagnoses and the like), and nary a thought was given to what the side-effects of that response might be, or whether those resources might have been better spent elsewhere. We just did it, and it turns out that the disease will have an impact on par with something else that we spend drastically less money on in any given year.

If you literally cannot fathom why a cost/benefit calculation might be appropriate here, you have lost perspective, and the OP's point is well-taken.