Well, that's the problem. Group climbing classes assume a lowest common denominator of zero. The more you've been out before taking a class like that, the less you're going to get from it.
Sounds like all you needed was to get out on some glacier routes with people. There is a debate on practicing rescue - I think it's useful (e.g. z-pulley), but there are glacier climbs you can do with a low risk factor without that.
A Basic class is nothing more than that "basic". The climbing clubs I am aware of have basic classes and intermediate classes, but no *advanced* classes. The point is to get bootstrapped so YOU can get started and then where you go from there is up to YOU. Clubs, and classes, are not, or should not be about the totality of you climbing knowledge and experience.
Helping newbies is a responsibility I think all climbers should strongly consider participating in - whether it's in a club, class, or just one-on-one mentoring. I would and have taken out newbs on climbs, but I am selective about it. I would not take a newb out on any route, but there are plenty that I would.