I'll answer for just myself...
A liberal Christian is a contrasting term to that of a conservative or fundamentalist Christian. A conservative or fundamentalist Christian takes the scriptures with a certain level of literalism that is required as part of their faith in Christ. For example, Jesus walking on water is a miracle that conservative and especially fundamentalist Christians would accept as a literal interpretation versus a more liberal perspective which might allow for the miracle to not be literal, but possibly based on some legend, or some miracle occurence of Jesus saving someone from drowning, etc.
As far as I could tell so far, a "liberal Christian" is someone who wants the "feel-good" side of Christianity without being too embarassed by all the supposedly superstitious stuff.
It's a matter of trying to form a realistic version of Christianity that is consistent with our modern experiences with nature. It's not fair to say which miracles did and did not occur, but it's a reflection of those events compared to our modern experiences and study of religious myths and legends to doubt the literacy of many of those accounts. There isn't a clear cut off between the Gospel of John and the Gospel of Thomas. If you look at the literature of the time, there are many, many unbelievable stories of miracle accounts of Jesus that are not treated as orthodox by even the most fundamentalist among us. There is no standard in deciding orthodoxy from non-orthodoxy other than what the early Church Fathers made their decisions based on, and the debates were anything but clean cut resolutions. In deciding to be flexible with the interpretations and literacy issues, it's not a matter of being embarrassed, it's a matter of being realistic in light of these and other issues.
I'd like to know, because if I am, then I can't understand why someone would choose such a blatant scheme of self-deception. Why not be more self-honest and profess himself an atheist? Truth too hard to handle?
Well, there are many degrees of separation from being a fundamentalist in the Christian religion to being an atheist. One could even reject religion altogether and still have a strong belief in God.
The issue of religion - especially a liberal interpretation of one of those ole' time religions, is quite straightforwardly simple as far as I can tell. It goes like this:
The universe is controlled and directed by laws that originate from some holistic order to the world. Part of the universe are humans and the institutions that they invent. As part of those inventions, this holistic order interacts on those inventions that provide meaning and purpose to human evolution. This interaction is a personal interaction in that holistic order (God) promotes and inspires religion as a means to better understand and spiritual mature as part of human evolution. As humans evolve and become more knowledgeable, the religions that are promoted and inspired by God naturally prompt changes in the religious perspective. Since humans began to write down their religious views, changes in these views eventually lead to opposition and contradiction in the ancient religious text (scriptures) from the evolutionary changes that must be made in order to continue to evolve and spiritually mature in the process. Along comes a religious leader in one of the religions who teaches the spirit of religion and who blatantly contradicts the laws of the old text, and is even executed as a criminal and seen as the Son of God by his followers and becomes their Christ. Now, for those who believe in that Christ, the law is no longer applicable to those who are committed to Christ, and those so persuaded are able to continue to spiritual maturity without the hinderances of ancient texts holding them back. They have adopted to the spirit of the law.
Hence, liberal Christianity, in my slanted view of the world, is not only a step up from fundamentalism, it is actually in line with the will of God in terms of humanity's spiritual evolution. It is anything but blatant self-deception. It realizes the purpose of religion and understands the need for spiritual evolution, and it is led by the inspiration of God in that path.