If you collapse all the forums posts into as many threads as the JP forums, I think it'll look about the same reply wise.

Anyway, in JP culture, "Do not cause trouble for others" is typical. From what I hear, they train using PF until they are confident enough to use the DF to do their runs, resulting in a generally more capable DF than western servers.
Another reason I heard is that the strategy used by DF players is synchronized, presumably through forums. That makes it easier for random people to work together because the fights goes the same. Homogeneity = efficiency, at the expense of creativity.