I wouldn't call it strange in that it really captured how So Cal became the So Cal we know today. I think Chinatown should be shown in every school where California history is taught. I can also see how those in the central valley-like yourself-could hate the movie-not for it's accuracy (it was very accurate) but for its accurate depiction of the movers and shakers in So Cal to rob the central valley of its water.
Speaking of "narration" one of my favorites is Redford's ending narration in "A River Runs Through It" (the ending music is special too)