The Middle East was fucked up way before the crusades and has been a battleground between major powers since the dawn of history, with your Hiitites and Egyptians, phoenicians and as assyrians all getting stuck in.
The Crusades was more a youngish upstart power trying to play with the big boys.
For most of the 19th and 20th century our involvement was overtly imperialist, although more latterly "protection of interests".
There were half assed attempts at humanitarian moral justification for the first gulf War, but it's really only since Kosovo that humanitarian grounds have been put forward as the actual grounds for intervention.