It's funny... according to Scientology, their views on ex-members are eerily similar to Watchtowers:
The Suppressive Person seeks to upset, continuously undermine, spread bad news about and denigrate betterment activities and groups. Thus the Anti-Social Personality is also against what Scientology is about—helping people become more able and improving conditions in society. As anyone can think of many examples of a Suppressive Person, this concept is not limited to Scientology. However, when such a person is connected to Scientology, for the good of the Church and the individuals in it, such a person is officially labeled a Suppressive Person so that others will know not to associate with them.
To be declared a Suppressive Person is extremely rare and results in expulsion from the Scientology religion. This occurs in instances of serious offenses against the Scientology faith and can also occur when an individual is found to be actively working to suppress the well-being of others. This can be done through criminal acts already recognized by society as unlawful or through the commitment of acts deemed Suppressive Acts in the Scientology Justice Codes—which includes the Suppressive Act of publicly renouncing the faith, an act which in Scientology, as well as almost every religion, is grounds for automatic expulsion.
When someone has been expelled from the religion, that person loses both his or her fellowship with the Church as well as with other Scientologists. The condition lasts until they have been restored to good standing. Once the person has been restored to good standing, the prohibition against fellowship with other Scientologists is lifted. Similar practices have been part of religious communities for thousands of years and have been recognized by courts of law as a fundamental right.