I try to avoid the use of the "should" word in all contexts except in relation to myself - and even then it's most often replaced with "could".
There are many, many thousands of examples of people using "should" when they "shouldn't". It's usually an attempt to give some sort of universal weight to their own prejudices. The examples you give are all noble in sentiment but have no universality. There are many, many qualifications for them.
"We should care for our children" until when? In spite of what?
"We should treat others with human dignity" what's "dignity"?
"We should do as we agreed to do" unless we find out something in the interim.