What do you know about the research done by contemporary macroeconomists? Anything? Do you know how it is taught in graduate programs?
If you did, you would know that all macroeconomists have opinions about where their assumptions (basic and otherwise) limit their models and spend their careers trying to extend them and make them more realistic and take them to the data.
I am not a macroeconomist but I will defend how my colleagues approach the subject. You don’t know how difficult it is until you’ve tried to formulate a model that you can actually solve and made an attempt to take it to the data.
The field absolutely does not operate on “unchallenged assumptions.”