Yeah, that'd probably be the problem. By reputation, sites like LavaLife and eHarmony are specifically geared to christian cultural norms.
At least one of them was created/run by a fairly pius individual who makes it the sites company policy to keep it that way. His watchdogs will hunt down and delete profiles that even mention Poly, swinging, being married.
Unfortunatly rightous types seem to miss the message about loving thy neighbors (too bad for us I guess), but on the bright side, rudeness is usually the extent they'll stop at.