Occupy certainly brought wealth inequality to more of a forefront of the conversation, but I wouldn't say it began the culture war. I'm old enough to remember the early 90s and the start of the permanent campaign and professional outrage of media. But the culture war has been going on since at least the mid 50s with desegregation.

Even in 1954, comedians were complaining about not being able to make a joke anymore.[0]

[0] https://www.truthorfiction.com/june-1954-jack-albertson-lame...