I don't see how you can take anything from that quote to say that a) he was or is a christian or b) that he was or is a catholic. You seem to doing a lot of reaching.
The 'faith' Picard might have may be in the Federation or in Humanities ability to overcome.
I do think its quite clear that the passage quoted from Losing the Peace indicates that JLP understands the imporantance of faith (in religious or humanist terms). I don't believe the faith is mentioned in reference to the Federation. It would be odd for him to be referring to a religious member of his crew, her faith in relogious terms, and then talk about his own faith in the Federation. Its not a logical leap.
Also, while it is not clear what "faith" JLP is referring to, he seems to be someone who doesn't necessarily believe in the religious/church-going aspect of faith, but in a more spiritual way without the religious obervations.
All that said, while the passage does not in any way point to what "faith" JLP may sympathize with more than others, since he is from LaBarre France, one "could" infer his parents where Christian in some fasshion. Assuming, the churches don't get destroyed by TNG era, there are a fair number of churches/cathedrals in
modern day LaBarre.
However, this is not based on anything in lit b/c I highly doubt that S&S would explicitly confirm any many cast human's religion. However, what readers imply themselves is all part of the reading experience whether implying religion, other motivations, etc. isn't it? Also, while I do not share the emphatic view that this passage is clear one way or other, how one readers implies what is meant vs. what someone else believes is still in the eye of the beholder. The individual here seems to be saying that a "case can be made for...." etc., etc., and he is right as are critics. However, what isn't in dispute is that the passage does note explicitly indicate that JLP is referring to Christianity, Catholicism, humanism, etc.
In addition, here are some religious stats from
modern day France (
by their government I think). Again, naturally, the future is not written in stone, and we don't know how the various Earth religions evolved in the TNG era, but I can't imagine France would have changed that much, but if it did, the country today has a healthy majority of Christians (predominatly Catholic).
The 2003 CIA World Factbook lists the religion of France as:
It is unclear where these numbers come from.
However, in a 2003 poll 41% said that the existence of God was "excluded" or "unlikely". 33% declared that "atheist" described them rather or very well, and 51% for "Christian".
When questioned about their religion, 62% answered Roman Catholic, 6% Muslim, 2% Protestant, 1% Jewish, 2% "other religions" (except for Orthodox or Buddhist, which were negligible), 26% "no religion" and 1% declined to answer.
The discrepancy between the number of "atheists" (41%) and the number of with "no religion" (26%) may be attributed to people who feel culturally close to a religion, follow its moral values and traditions, but hardly believe in God.
All that said, this is just a chat amongst fans. The passage used is clearly vague, but there may some reasons to "assume" something JLP's religious upbringing based on what we know of his country/town of birth (using modernin information, but infering about the future).