People act differently in groups, it is human nature to hold back truth to fit into the group-think. This is why God told us to meet with like-minded people who love the Lord so that the purpose is to edify one another in the Lord solidifying our motivation to remain faithful to the Lord Jesus Christ Who lives in us and to His principles.
The larger the group the worse the problem of capitulation to the collective mindset.
In secular unbelieving groups the purpose for gatherings is most often worldly ideas that promote self.
In the group of born-again believers the purpose for gathering is to build one another in holiness for growth leading to Spiritual maturity.
Mankind tends to emulate those they spend the most time with, the reason it is so important to choose our close friends wisely.
1 Corinthians 15:33 "
Do not be deceived: “Bad company corrupts good morals.”
It is interesting that it is not the other way around, one strong believer in a group of unbelievers can have little to no effect because those who are the majority shrink from listening to the one person in the group who is a dissenter.
The majority really does rule in gatherings the very reason we need to protect our Spirituality by making our companions those who love the Lord as we do.
The only reason to ever be in a gathering of unbelievers is to speak the gospel boldly and leave when no one will listen.
Matthew 10:14 " 14And if anyone will not welcome you or heed your words, shake the dust off your feet when you leave that home or town."
Nowhere in God's Word do we see Him telling us to be friends with unbelievers the way we should be close to our brothers and sisters in Christ.
2 Corinthians 6:17
"17 Therefore, come out from their midst and be separate,” says the Lord. “And do not touch what is unclean; And I will welcome you."