Circle management is optional. If you want to use it like Twitter, you can. Just dump everyone in one Circle and spray your content indiscriminately to everyone in it.
The point is that to use this feature (which is potentially a great feature) requires you to do shit work.
Yes it's an optional feature and people can not use it but frankly the whole product is optional and people can not use it.
If you're going to put a feature in your product then you should do so in a way that makes it as good as it can possibly be - and that includes reducing the associated shit work.
But you don't need to use every Circle - you can dump everyone you know in one Circle and leave it at that.
I've got to say, this is very much a complaint that doesn't appear to have a good solution. Beyond any sort of simple AI that groups based on last name, school or employer (like Facebook does, I guess), there's not much to go on when it comes to automatically creating Circles.