Cultural insensitivity

Subject: Cultural insensitivity 

How can we judge 'others' except in humanistic terms. How can we hope to judge 'others' from widely disparate cultures when their culture makes up so much of who they are and yet we remain are ignorant of that culture.
Human beings are made up of flesh and blood, the one thing we all have in common. In fact it's this fact which allows others to persuade us into believing we are all the same.
I'm reading a book by Edward Said called Orientalism in which he disparages the West for having a collective view of people living in the Middle and Far East. 

Is it ignorance or arrogance which allows us to ascribe a collective description to people who are far more diverse than we in the West, with a history much older and founded in millennium old civilisations, far outstripping our own which were marvels of education and philosophical conjecture whilst we were still running around in animal skins.
The individual Egyptian or Syrian, the Hindu or the Chinese dynasty's were expressing their collective individualism a thousand years before the major religions, Christian and Muslim had been formed.
Our willingness to presume that we know best is based on the ideal of democracy and fixed term governments but is at odds with much that we find in two-thirds of the world, from Africa, the Middle East to Asia, where the bulk of the worlds population lives.
Interwoven amongst those races and tribes are a myriad of customs and value judgements which are very different to our own and yet, never the less, we ride roughshod over them on the presumption of military might and the observance of our system of law which presumes ownership and contractual obligation.
To gain knowledge of things outside our common experience is often met with the comment "why should I, what do I gain". What do I gain usually means " is there anything in it for me". Perhaps, not before time, we would do better to try to understand, not only the foreign view but also ourselves as a counter point to our seeming cultural insensitivity.