BelongingBelonging - whether to a family, a "race", or a nation - is a place where the individual and the sui generis society meet; a kind of frission between two levels of reality. It is possible that our tendency to form groups has some sociobiological origin. (I tend to think so, personally.) Regardless, our habits of forming groups in today's society (even the "pre-modern" ones) goes far beyond that simple original biological tendency.
Let's take marriage, for example. The sociobiological tendency (if it exists) would be to pairbond for a practical reason. Fine - but that alone isn't enough to explain all the cultural cruft around it. Why the wedding rings? Why the ornamentation, the gifts, the dowries and dances and smashed glasses? Why the tuxedoes and the justices of the peace, and why do we care if gays have it or not?
It's easy to conjecture - and even demonstrate - lots of reasons for the above, but ultimately they *are* cruft. Sometimes useful cruft (wedding bands), or fun cruft (dancing and glasses), and sometimes pointless cruft (arguing over gay marriage). But it's all cruft.
Roman Catholicism is very similar as well. While it has the "core" of the faith - the Nicean Creed and the Bible - there is more beyond that. These other aspects of the faith - often condemned as "man made" by fundamentalist Christians - are logical extensions of the things already stated. For example, if the saints are with God, and if those in Heaven can hear our prayers, therefore it makes sense to ask saints to badger God on our behalf, the same way we would ask friends to "pray for us". It's a whole set of logical and reasoned thought built on the consequences of what is in the revealed text. (I understand Judaism's Talmud serves a similar role, and that there are commentaries on the Qu'ran, but I don't know enough about them to comment intelligently past that statement right there.)
That, however, is also where the problems come in. There are many Roman Catholics, for example, who disagree with the Church's outright ban on contraceptives or recognizing gays (yes, I'm avoiding abortion on purpose). I overheard one Catholic yesterday relating how her priest disagreed with the concept of suicide being a mortal sin (that is, one that severs one's link with God and dooms one to Hell), since that priest could not concieve of a loving God who would further punish a depressed person. (We're ignoring both the fact that Jesus could be concieved of as being sent on a suicide mission or the rather more internally consistent view of a suicide's Hell from the film _What Dreams May Come_.)
Yet these people (gladly, reservedly, or unabashedly) identify themselves as Catholic.
You see this in any group. It may be more suppressed in some (contrast the GOP's image of homogenous ideology with the Democratic infighting over the last 20 years), but this does exist.
This Is Not A Problem. If done skillfully, this can strengthen groups while simultaneously divesting them of rigid control issues. 9/11 (yes, I went there) shows our natural tendency to group together, especially when faced with a common challenge or threat - and the utter botching of that national energy. By rigidly proclaiming a "with us or against us" view, by insisting on homogenous thought, large numbers of people found themselves unwilling to even be associated with the USA over the last eight years.
No group - even one as small as a family - can be homogenous for any length of time. In a family, our feelings for each other are fluid as relationships deepen, change, and grow. The core - that identification as "family", that fundamental caring for each other - may lie underneath anything from affection to ignored neglect to irritation to intimacy.
Therefore, rigid expectations of a group - what it is like, should be like, and what is required of its members - can lead one quickly to thinking that one is no longer a member of that group. (Or worse, having another group member tell you that you're not a Real GroupMember.) That is a quick way to find one's group shattered by the side of the road.
Regardless of how good, bad, or simply uneven the surface may be, simply remember that the core identification remains. Work on the problems, but together, even as you differ. In that manner, we can pull together and accomplish so much more.