this article will probably cover it better than I can.
but there was only ever the "big blocks" camp to begin with. Starting with Satoshi and Gavin Andresen. The "small block" movement is the newer "vision" and didn't/wouldn't exist if not for the financial interest suddenly employing the core developers.
The market has wanted bigger blocks for YEARS, and each attempt was slandered/DDoS'ed/attacked. Bitcoin Cash is the result of the market finally getting what it wants.