Theory: aerodynamic-appearing is strongly correlated with "visually attractive".
It's visual language for "we can spend money on excitingly curved hull plates and unnecessary fairings, etc., just so we don't have to look at a starship that looks like a boiler factory had a terrible accident when attempting to mate with a steamroller".
(Which in turn is symbolic language for "we are rich and have a high culture, unlike you primitive savages from beyond the Marches".)
nyrath