The undermining of the great value and heritage of Western civilization began decades ago. The American and British school systems purposefully changed the definitions of both civilization and culture, so that the two were presented as equal, which these two groupings of people are not.
The ideology behind the destruction of the idea that the West has had a superior civilization rests in two false "isms"-communism and atheism. However, other "isms" know attack Western inheritances as well.
The reasons the proponents of those two above mentioned systems undermined the history and heritage of the West are simply this-hatred of Christianity, specifically Catholicity, and hatred of the Church.
I saw the rot creeping in when I was teaching. More and more history books, as well as philosophy books, no longer criticized the pagan ideas behind pagan civilizations. In fact, one history book still used for the Cambridge international examinations includes a discussion question as to whether Hitler was right or wrong.
Relativism ruined objective thinking to the point that one of the most evil national parties based on neo-paganism and anti-Semitism, could be considered a "correct" or viable possibility.
The Catholic Church created Western civilization, out of the ruins of the ancient world. The Jewish revelation of the Old Testament, which is ours, and the great civilizations of ancient Greece and Rome, blended to create the Judeo-Christian civilization of Europe.
Cultures are not civilizations. This blurring of distinctions purposefully introduced into all levels of education in the 1970s and later, grew out of political correctness. No one could "judge" any longer between a small cultural grouping and a real civilization with currency, trade, education, laws and legal systems, and religion, not merely cultural practices.
The rot won. Now, few of the Millennials can distinguish between a heritage based on the rule of law, religion and strict norms for society, in opposition to cultural identifications of a tribe.
No one is allowed to think from these older definitions, except, of course, Catholics.
Catholics know which institution began schools, universities, hospitals, legal systems, while raising the status of women and the poor. Art and music came out of patronage from Catholics. The most beautiful buildings in the world, the great Medieval, Renaissance and Baroque Cathedrals, came out of the architectural ideals of the classical and Catholic world. The Catholic Church created Western civilization and that is why those who are communists and atheists have striven to tear down that great inheritance.
One reason I home schooled was this denigration of Western civilization. One reason I got a Master's Teacher Certificate from NAPCIS was because of this denigration of Western civilization. One reason I teach is because of this battle, raging, but sadly, in most countries of the West, won by those who hate the Church.
We can all be proud of our cultural backgrounds, but we cannot pretend that all cultures have equal value or that cultures are civilizations. Such confusion and such pretensions have destroyed the best educational systems in the world. Such confusion and such pretensions have destroyed logic and the use of reason in many areas of life. Such confusion and such pretensions have made Catholicism just one more religion, instead of The Religion.
I suggest re-reading these two documents.
http://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_20000806_dominus-iesus_en.html
http://www.vatican.va/roman_curia/pontifical_councils/interelg/documents/rc_pc_interelg_doc_20030203_new-age_en.html