Orthodox economists reduce economic agents (people) to instrumental rationalists, to calculators of private advantage. They're preoccupied with the mental module, as it were, that supports capitalism, ignoring or downplaying the facets of personhood that complicate this kind of society, to say the least. Orthodox economists posited Homo economicus, reducing personhood to a kind of calculation that a computer could perform, because that's what justified these economists' naturalistic defense of capitalism, their use of arcane maths in their models, and the analogy between physics and economics.

Abstracting away the subjectivity of economic agents, and treating them as sociopathic calculators of "utility" is hardly the same as stressing the subjective, irrational aspects that make capitalism a dubious, potentially self-destructive enterprise.

The point about economic objectivity is about the economist's platonic abstractions from real-world complexities. The emphasis on math leaves the impression that economic systems are abstract, potentially eternal objects, in which case they have an optimal way of running that lasts into the very long term. And government intervention is supposed to impede that efficiency because government isn't properly modelled as just another member of Homo economicus. Government would be a monopoly that's no part of a functioning capitalism economy.