The economics and constraints of shipping favour ugliness in this era I think. A sailing ship kind of has to be pretty to be good at its job, and a lot of early passenger steamers inherited the same design features which made sailing ships pretty. While modern shipping is much more efficient the constraints favour maximising how many containers (or tourists) you can fit on a ship instead, which produces boxy, slab-sided things.

Curious readers might appreciate another "monstrosity" for it's time, the SS Great Eastern, which was built nearly 100 years before the SS United States:

https://en.wikipedia.org/wiki/SS_Great_Eastern