The Bible says, Do not forsake the gathering together with fellow beleivers. These churhces have decided to "focus on the family" rather than "focus on Christ."
Priorities used to be God, family... Now it's Family, maybe God.
These folks are simply setting their own schedules. They are not forsaking anything.
I know churches who meet once a month...that's how they're organized. Their leadership makes that call.
In this instance, these folks have made a local decision based on their analysis of the situation. I think they send an awful message, but it is not a sinful decision, imo.