[squidsk]

Primary usergroup is irrelevant, as long as any group has a deny, primary or secondary, the user will not have access.

If you want members to gain access after contributing, have one group with no permissions, then when the member contributes, remove that group. You could also use the promotion system in the same way, so that they get promoted out of the group with the no permissions attached to it.

As for whether or not it should work like the forums, it does, its modeled on how the banned groups work in the forums. It was design decision by the creator, so unless you can convince them to change it, or change it yourself it isn't likely to change at all.