That's like saying that there is no American culture because there are 328.2 million residence. I bet that if you swap the residence of Indonesia (273 million residence) with the residence of America, you will notice a lot of cultural differences.
Pedantic notes aside, the point is that it's the least surprising thing ever to find that some subreddits have one attitude towards $THING and other subreddits have a different attitude. The site has hundreds of millions of active users.