I would imagine it's very rarely that administrators and moderators don't respond to private messages, and if they don't there's most probably a specific reason for it.
I suspect you personally have observed administrators not responding to your private messages. This is because we do share information, and know that you contacted multiple administrators about the same subject. As such, logic would dictate that we don't all need to respond and address the same query.
LucasForums also has distinct areas which are governed by different administrators. If you contact an administrator who rarely gets involved in a certain area about something pertaining to that area, chances are it'll be immediately forwarded to a relevant administrator.
We most certainly don't just sit here swinging ban hammers around. We share information, and we have a good idea of what's going on in the community despite its size. We definitely don't give people the cold shoulder; we'll make sure the person in question gets a response to their query from someone who can help.