The answer to this
question is partly semantics so we have to clear up the definitions first.
Progressive thinking is associated with the Progressive Movement which operated
from 1870–1940. Those Progressives agitated to reverse worker exploitation and
corrupt politics. They were successful in that endeavor.
American
Liberalism did not appear until after World War II. President Truman made
opposition to communism a key component of his administration. That decision
isolated the Progressives because they had been traditionally against foreign
intervention. The actually ran Henry Wallace as a Progressive candidate against
Truman in 1948. When Truman won, Liberals took control of the party and the
Progressives became marginalized until the 1960s.
I say American
Liberalism because, as at least one other person pointed out, it was very
different that the European version we call “Classic” Liberalism.
American
Liberalism prospered until the early seventies, when it got a bad name over the
failure of the welfare system. That is what I think you mean by “ashamed”.
Today’s Liberals do not want to be associated with big government programs that
do not work and waste money.
As Liberalism
waned, the Progressives rose again, starting during the George W. Bush
administration.
Progressives sit to the left of
Liberals in the Democratic Party. They are more aggressive about wanting change
even to the point of changing the government. They are very sensitive to the
poor and other disadvantaged groups and they hate capitalism as exploitative.