I hear quite a bit of criticism about Jehovah's Witnesses enforcing 1 Corinthians 5:9-13. While Jehovah's Witnesses have a formal system of maintaining the organization's core values; egocentric, self-worshiping secularists have an informal system of rejecting those of whom they have nothing in common with.
http://www.objectivistcenter.org/cth-32-390-Religion.aspx
Most major religions have believed in the existence of a supernatural realm, a realm beyond the natural world of physical objects and bodies governed by causal laws, the world we perceive with our senses and can study by rational methods. Some religions posit a personal god (or gods); others believe in impersonal supernatural forces. (See George Walsh, The Role of Religion in History, chapter 1.) Objectivism rejects any notion of the supernatural as incompatible with the objectivity and regularity of nature as identified by reason. There is no credible evidence of miracles, magic, or other supernatural phenomena in nature.
The dominant forms of religion in our culture posit a personal god, a Supreme Being, who created the world, is omnipotent and omniscient, imposes moral duties on man, and expects worship. Those who accept this idea have the burden of showing why such a hypothesis is necessary. In this regard, Objectivists are atheists because the arguments for the existence of such a being are not sound. Objectivists reject the existence of God for the same reason they reject the existence of elves, leprechauns, and unicorns: because there is no credible evidence of such beings.
http://www.objectivistcenter.org/cth-32-541-FAQ_Objectivism_Family.aspx
Objectivism holds that the fundamental standard for all relationships is the trader principle. This principle holds that we should interact with people on the basis of the values we can trade with them - values of all sorts, including common interests in art, sports or music, similar philosophical outlooks, political beliefs, sense of life, and more. Trade, in this broad sense, is the only proper basis of any relationship—including relationships with members of our families.
Many people are indoctrinated with the belief that we must automatically love family members simply because they are family. This is the view expressed in bromides like "They're still family" or "Blood is thicker than water." This view is not compatible with the trader principle, since we may not gain any values from certain family members, and hence may not love—or even like—them.
There is a distinction between the family that we are born into and have no choice about—parents, siblings, relatives—and the family we can choose for ourselves—a spouse. Since the former relationships are unchosen, it would be a rare coincidence if we could truly love each member of our family for who they are. The likelihood of being born surrounded entirely by people with whom we share core values is not very high. Affection for our family members would be a genuine reflection of shared values only if we could imagine feeling this affection even if they weren't family.
------------------------------
I've known many who are rejected by certain family members after becoming one of Jehovah's Witnesses. Religion and politics are very divisive. Considering the fact that you can get reinstated, the formal system seems better than informally cutting someone off. This “informality” doesn't allow for any dependable way to be reunited with friends or family.