Not surprised. Bodies of elders are free to set "congregation standards" to determine who is "exemplary" enough for "privileges." Often these standards relate to dress/grooming--such as the infamous example from a few decades ago of some congregations requiring brothers to wear white shirts when giving talks.
In more recent years, I've heard of congregations not allowing JWs to serve as pioneers or Ministerial Servants if they go to nightclubs or rock concerts.
Of course, this varies from congregation to congregation. There has been no official condemnation of Facebook/Myspace/etc. from the Society. But I expect more local needs talks, mentions from the platform at circuit assemblies, etc., in the coming months and years.