The term “Liberal Catholic” is many times associated with the phrase “Cafeteria Catholic”.
These people tend to want to pick and choose which dogmas and rules of the church they wish to observe. This goes anywhere from not attending Mass on a regular basis to espousing Civil Divorce, Abortion, Contraception, Gay Marriage, and Women Priests. In their error, they actually believe they are Catholics in good standing.
Other Liberal Catholics are those who were born to non practicing Catholic parents, yet were Baptized in the Church, but were never Catachized to any great extent. Most of these people consider themselves as Catholics, even though they attend Mass only on the Holidays,
I would say the term “Liberal Catholic” precludes those who are practicing Catholics in full recognition of the Faith.
If one is truely a Practicing Catholic, one is educated in their faith and is orthodox in their beliefs and practices. This, in itself would preclude their being political liberal, unless you are using the term liberal in place of tolerant.