It is much better to define acceptable boundaries on actions and let people believe what they want if their actions do not violate those agreed on boundaries.
People absolutely heed laws that they find personally inconvenient but are afraid of the penalties (parking restrictions, paying taxes, loud music and that is not even stepping into hot button topics).
The reason Swiss stayed democratic is likely not because they share universal, similarly understood values, but because they feel that their system that only defines acceptable norms is working okay as is.
Please do try this, I've tried it in the past, and always been able to come up with counter-examples to whatever I came up with. It's surprisingly hard.
"Always be kind" is one example that for me should obviously be shared with everyone, but it's almost disgustingly easily to come up with whole cultures or countries where this is actively seen as a "bad thing" because of reason X and Y, or has to have exceptions because of Z.
Kindness isn't really a value, though.
Shared values are simply things that people decide are important for a society to function as well as possible. Respect for human life and dignity, for example. Good thing right? How many mental gymnastics does somebody have to go through to find some exception to that?
Tell you what though, if I come across somebody who says that they don't respect human life and dignity, I am absolutely going to avoid that person and shun them from any kind of society that I am a part of.
Why not? I think everyone deserves kindness, and I'm not alone in thinking that.
So even something that for me is obvious, it isn't as obvious for everyone.
> Respect for human life and dignity, for example
It's very generic, and subjective, which again leads me to believe not everyone would agree on what it means.
For example, does "respect for human life" mean you should let people live where they currently live, if they and their family lived there for 100 years say? Lots of Israeli settlers would disagree with that, but for me that would be a sign that someone doesn't have "respect for human life".
> if I come across somebody who says that they don't respect human life and dignity
Of course everyone will say "Yeah, of course I do!", but where the rubber meets the dirt is how people define that. Not being kind to people who made mistakes for example, wouldn't be "respecting human life" for me, but you might disagree, as you think we shouldn't be kind to people who committed murders, but you would still claim you "respect human life".
