A term which the Roman Catholic Church uses to describe people of different religions.
"Disparity", according to the OED, is "the quality or state of being of unequal rank, condition, circumstances, etc.; inequality or dissimilarity in respect of age,
amount, number, or quality; want of parity or equality." "Cult", in this case, seems most likely to take on its general religious meaning: "a particular form or system of religious worship; esp. in reference to its external rites and ceremonies." In this usage, it does not take on its current negative connotation, but its earlier, neutral one. So two people who have a disparity of cult between them would simply be of two different religions.
This is all well and good on the surface: of course people have different religions and religious beliefs. There are an awful lot to choose from, after all. However. The Catholic church seems to distinguish people based on their baptismal status, as opposed to their individual religion. Interesting. So people who have been baptized, no matter what Protestant sect (and I probably should not use this term either) they might belong to, are not considered to be in disparity of cult with Catholics.
So. What then does the Catholic church think of baptism, that they are distinguishing people based on baptism as opposed to what religion people say they are? The Catholic catechism defines baptism like so:
1213 Holy Baptism is the basis of the whole Christian life, the gateway to life in the Spirit (vitae spiritualis ianua),4 and the door which gives access to the other sacraments. Through Baptism we are freed from sin and reborn as sons of God; we become members of Christ, are incorporated into the Church and made sharers in her mission: "Baptism is the sacrament of regeneration through water in the word."5
Baptism then causes people to be reborn in Christ, essentially. To a degree, then, it makes sense that the church considers all baptized people to be on the same level. It certainly sounds like a good thing: different Christian religions are all essentially based on the same thing, so considering members to all be Christians in their own way would be a good thing. At least there aren't going to be any more Reformations and Counter-reformations and Inquisitions within Christianity.
However, the key phrase there would be "within Christianity". If all Christians are equal, are people of other religions less equal? It would appear so. Although the phrase itself does not specify who is more equal -- "disparity" just indicates a difference, after all -- it does specify that people who believe different religions are unequal. The church may simply be calling all religions different. It also may be calling Christianity more equal than other religions. It certainly implies as much: if baptism is what allows a given church member to have a "life in the spirit", then would an unbaptized person be considered to have no spiritual life? Worse, would they be allowed no spiritual life? It seems possible that the church would consider them as sinful beings, without the possibility of redemption unless they are baptized.
On the other hand, this definition of baptism does not specifically or explicitly exclude other methods of spiritual redemption. It just says that within the church, this is how members can be redeemed. It is the Catholic catechism, so it makes sense that the Catholic point of view is covered. But why are other religions unmentioned? Is it because they are not considered to have valid forms of redemption, or simply because they are not the topic at hand?
Well. Let's see what happens further down the catechismal page:
VI. THE NECESSITY OF BAPTISM
1257 The Lord himself affirms that Baptism is necessary for salvation.59 He also commands his disciples to proclaim the Gospel to all nations and to baptize them.60 Baptism is necessary for salvation for those to whom the Gospel has been proclaimed and who have had the possibility of asking for this sacrament.61 The Church does not know of any means other than Baptism that assures entry into eternal beatitude; this is why she takes care not to neglect the mission she has received from the Lord to see that all who can be baptized are "reborn of water and the Spirit." God has bound salvation to the sacrament of Baptism, but he himself is not bound by his sacraments.
Right! At first glance, this looks pretty harsh for non-Christians. But then you see that "the Church does not know of" any other certain methods of salvation. This then does not completely exclude other methods of redemption, presumably offered by other religions; it states merely that the Catholic church does not know that these other methods work. However, they do apparently know that baptism works. This is interesting in itself; I was under the impression that Catholicism was based on faith, which by definition cannot be known. Hmm.
"Disparity of cult", then, can be seen as a fairly neutral term. It does have some disturbing underpinnings, but the church is not quite claiming that they offer the only method of salvation; as such, I don't think they are claiming that they are the one, true religion (at least not publicly -- that would be an inept political move, though, so who knows). Thus they are not overtly considering the baptized more equal than the unbaptized. They are simply distinguishing between those who have one known possiblity of redemption and those whose possibilities of redemption are unknown.
4 Cf. Council Of Florence: DS 1314: vitae spiritualis ianua.
5 Roman Catechism II, 2, 5; Cf. Council Of Florence: DS 1314; CIC, cann. 204 # 1; 849; CCEO, can. 675 # 1.
59 Cf. Jn 3:5.
60 Cf. Mt 28:19-20; cf. Council of Trent (1547) DS 1618; LG 14; AG 5.
61 Cf. Mk 16:16.
Also check out: http://www.newadvent.org/cathen/05037b.htm (although I read this after I wrote the above)