Yes a whole raft of questions coming to the surface.
The way I see it, one of the fundamental problems that we have in the West is the devaluation of what is good/wholesome. People simply don't value goodness any more. Without that core aspect the search for what is wholesome and unwholesome cannot even begin. And as you say- then there needs to be externally applied force- to be TOLD what to do and not to do, in its absence.
Also the dhamma is a thinking man's teaching. There are no 'rules' from above. Only principles and guidelines which lie at the core of this path we are trying to develop. It is up to us to apply them or not. It gives you responsibilities for your own life, your family and your society; ie the actions which you perform, which affect your life, family and society must take place after contemplation, whether it is wholesome for yourself and others. If it is not clear after thinking,then ask someone else on the same spiritual path. if it is still not clear, it is very likely it is not very important!
I don't think the Buddha ever set out to change societies, but targeted individuals; which of course changed societies once a critical mass was achieved. So this is not a set of rules for everyone to follow. It is a rich multi-textured collection of teachings, we can use for our own development as individuals. And that is the intelligent way to set out a teaching. Not knock someone on the head with a set of rules for all to adhere to, which is a suboptimal method of teaching.
The modern worlds reliance on science must be questioned. Scientists will always say that their conclusions aren't permanent. However most people in society will take their conclusions to be fact and forever true, without even knowing that they have done that. From year to year, what is 'true' in the eyes of science changes and the whole of society has to keep up with half truths. So if you base your measure of the world based on science you are on shaky ground. It is something to think about.
Science has little to say on what is wholesome and what is not. So you are not going to get your guidance on that matter, there. It helps to keep this in mind:
To do no evil;
To cultivate good;
To purify one's mind:
This is the teaching of the Buddhas.