but in practice it is just a cieling that keeps us middle class from passing the estate tax barrier.

Sounds familiar..

So, it's Sold to us as a way to force the rich to keep their money working and benefiting the economy, which I have never seen being something that had to be forced on them, nor do I understand what harm it would cause if they didn't,

And, as it works out, it looks more like a mechanism that protects the old money families from upstart competition. The laws force sales of the successful business that a family is building up before it's quite big enough to threaten them.