I thought it was because education back then focused a lot on Greek and Roman times.
Greek Revival was the architectural fashion at the time when the vast majority of them were built, that’s why. Once established it then became “the look” and so has been replicated long after Greek Revival ceased being the architectural fashion of the time.
In years past, buildings were architecturally interesting and beautiful, not steel and glass monoliths.
I think the main reason is they simply look great.
Many think the Parthenon was the most beautiful building ever.
Because people like the way it looks.
Legitimacy.
But Davis’s most lasting legacy as a nation-builder, both figuratively and literally, was as a prime mover in the mammoth project to expand the United States Capitol from a small, cramped, statehouse-like building with an attractive central rotunda into a sprawling, magisterial seat of government with separate, marble-faced wings for the Senate and House, and a soaring new dome made of cast iron. The U.S. Capitol, as we know it today, would never have existed without Jefferson Davis. In many ways, it is his building.
If I ever became a President and I ended up accomplishing important things, I would want people to build a Greek temple because they last forever and that I was really important! Lincoln and Jefferson both got their Greek temples and they’re awesome!
We are indebted to the Greeks, not the Roman’s, for what is great, judicious and “distinct” in arcitechteure....
Although unknown at the time, the use of the classic Greek temple style for banks and Treasury buildings was historically apt in that the Parthenon and other Greek temples were originally used in part as municipal treasuries.
Look at the gargantuan horses being restrained by muscular figures that cap the Eastern end of the Federal Trade Comission building — a choice neo-classical iceberg. They represent government control over the wild horses of unrestrained capitalism. What they actually and unintentionally reflect (aside from kitsch) is an oppressive government scaled up to up in the size of The Incredible Hulk. I think this is the key to understanding why the neo-classical style was so popular for federal buildings back then, its massive forms were intended to belittle and awe the individual and stress the strength of the state as a collective.
“Why Do So Many Public Buildings in the U.S. Look Like Greek Temples?”
Good sense and good taste ?
Greek = Stone = structural efficiency
There was no structural steel or concrete.
Greek and stone was the way to go for monumental buildings
Read “The Fountainhead” - it explains why.
For example, properly designed columns don't have a consistent taper from their base to capital. They have a slight bulge roughly 1/3rd up from the base and then taper. If they didn't have this, columns would appear concave to the eye.
Everything they did was based on the diameter of the column. Even the height of the column is based upon its diameter. The diameter is then broken up into minutes and seconds and with these increments the base, capital, architrave, fascia, soffit, moldings, etc. are determined.
When Athens, Rome, etc. were being 'discovered' by the English and others, their architecture was brought to western Europe and later to America.
Architects like Inigo Jones and Christopher Wren, both English, and Charles Bulfinch and Asher Benjamin, both American, popularized the ancient designs. America was keen to adopt this architecture due to it being fashionable during America's birth with its foundation on ancient governments.
The Greeks had learned the art of making eye pleasing design in their temples housing their idols. They apparently had learned to use such principles as the golden ratio. Since their architectural designs were pleasing to the human eye they were used by our early architects because they appreciated their design quality.
https://www.goldennumber.net/parthenon-phi-golden-ratio/