They 'were' liberals. Not 'are' liberals. They are dead. They have been a very long time.
As someone once said, 'the past is another country; they do things differently there.'
Progressives, generally, want to make progress; conservatives, generally, want to conserve things the way they are.
Progressives are pragmatists, they seek the best course of action based on facts and evidence, not partisan ideology and dogma; they embrace change and diversity and advocate for a consistent application of the Constitution and its case law.
Conservatives not only seek to keep things the way they are, but as fearful reactionaries they seek to turn back the hands of time, they pursue a myth of an idealized American past, a fantasy that never existed in the first place. As reactionaries conservatives fear change, diversity, and dissent and are often at odds with the Constitution and its case law accordingly.