"Carpet bombing" is perhaps a hyperbolic term, but widespread application of DDT in the southeastern US was, in fact, a central component of the effort.
It's very possible getting rid of malaria made this was a worthwhile, even given our modern knowledge, given the treatment options available at the time.
Large-scale medical treatments are always a difficult area, because almost no treatment, or course of action, is risk-free, but malaria was awful when it was more widespread.
It's such a neat method because it is so inexpensive too. You take a bunch of mosquitos, irradiate them with just the right dose at the right time and then release them en-masse.
Its not really that we know better. We known more and we know there is more of a trade of than was assumed then.
But to know better would mean we would have done anything different back then. If the choice is a silent spring (hyperpole, but okay) or dead babies from malaria in the US, no politician is going to align with the "I support dead babies party" and nobody is going to listen to those who do.
Until they banned DDT ostensibly because it was a threat to 'wild life'. I'm sure it affected people very adversely (it's rumored that DDT was one of the major causes of polio). Right now there will be chemicals which are widely used which fall in the same league.
https://stacks.cdc.gov/view/cdc/100616/cdc_100616_DS1.pdf