Science is iterative yes, but when we say that we mean we cannot know everything all at once so of course some theories will be wrong. But, what the commented is saying is that it is not just that we do not know everything so our theories are incomplete, it is that the "scientifically derived knowledge" that we do know, is mostly false.

Their are entire disciplines with a 80%+ false results rate. This is not an iterative process, this is we did a scientific study and found with 99.999% certainty that X is true, but its not. This is not iterating towards truth, this is just claiming to have authority and being absolutely wrong. And given how science tries to be iterative, these wrong results can then be used to derive more wrong results. Iterative processes cannot function with incorrect axioms.

You cannot just hide behind science as an authority and assume it will fix everything and you can just unthinkingly trust any results it generates.