Chello y'all! To answer your basic question Inquirer no it is NOT a requirement to join a BGLO. My chapter is like LadyAKA's - we attend church together at least once a year. Prayer and meditation comes up on the regular and it's always a joy to see Sorors at church and whatnot. The question you pose is really up for discussion with your spiritual guide whether you call that being God, Allah or Spirit. Personally I don't know what I would do without my church fam but that's me.
As for the smokers and drinkers up in the church - that is to be expected! Not everyone IN the church is IN the church. Like my sisters said, don't worry about what they are doing just focus on yourself! Hope my $.08 helps.
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We will remember not the words of our enemies but the silence of your friends. - Martin L. King Jr.