Ha, you've actually hit upon one of the great debates in the historiography of the crusades. There are arguments on both sides, but there are two main points that I'd like to address. First, the idea of applying colonization in the modern sense to the Crusader States of Outremer is more than a little anachronistic. It rings similar to the sophistic attempts to identify the "race" of Ancient Egyptians, as if a modern identity could possibly apply to a civilization 5000 years older. Additionally, the Crusades bear far more similarity to other conquests of subject peoples by an invading martial class than they do to anything we might recognize as Heart of Darkness style colonization. The Viking conquests of Russia, Normandy (and then to England), and the Mezzogiorno provide instructive examples, as does the Seljuk invasion of the Near East. I could go on providing examples, but I hope I've been clear.