Many a culture had thought they carry civilization to the word, such thinking is nothing new or surprising, which doesn't make it objectively true.
Linguistically, the word "Islam" may really be part of the word "Istan-bul":
"... Turk. name of Constantinople
, a corruption of Gk. phrase eis tan (ten) polin "into the city," which is how the local Gk. population referred to it. Picked up in Turkish 16c., though Turk. folk etymology traces the name to Islam bol "plenty of Islam." Gk. polis "city".."http://dictionary.reference.com/browse/istanbul