@magdo,
As the noble Koran contains the greatest legislations, the best morals and the most eloquent instructions coming from God, Muslims get interested in respecting and glorifying it whatever it is.
As the holy Koran contains the sacred words, so it refers to it and it is a symbol for it, so respecting and venerating the book is respecting and venerating the holy Koran, and offending it is an offence to the meanings and the legislations it has, so we get angry when someone offends it. We see nowadays that countries get angry and sometimes start violent wars when offending a symbol like a flag, is the flag the country or it is just a symbol to it? Offending the symbol of a country is an offense to the whole country, also offending the president of a country or a delegation or anyone who represents it anywhere, here offending the symbols is an offense to what these symbols represent.