I thoroughly agree that all voices here are equal, from the person making their first post to those who are more prolific and/or have been members for a longer amount of time. I have been a member of many groups and forums, and I have always held to the standard that all have equal value and worth, regardless of how new or old they may be. If someone belongs, then they belong. I was once part of a forum focused on healing a specific issue, and I used to buck at those who claimed an elder status because they'd been active in the healing process for longer.
I'm curious as to what you consider selfish behavior. If you're warning someone against it, then it is helpful to clarify what you mean. Otherwise, someone may unnecessarily question themselves and feel less confident when they're doing just fine, if that is their natural inclination. I'm not suggesting you own other's perceptions or their self worth, but an amorphous statement can lead to confusion, and confusion isn't helpful when I think your motivations are in fact to be helpful.
Finally, I will say with respect that I disagree about bonding. I've been in other controversial groups, and such claims about standing together or falling apart have been used to shut down personal autonomy, important questioning, and valuable dissent. Based on difficult life experiences and subsequent lessons, I would not want to bond with everyone in any group, I maintain my boundaries, autonomy, free will, and critical thinking. I participate and bond only over the reasons for the group existing, as long as I agree with those reasons, and as long as the group continues to benefit me in safe and healthy ways. For example, families. Families and human bonding are necessary, but if the family or the bonds are toxic, then it is, for me, far better to be without that family. Same with any group, no matter how much I need what it purports to provide.