Why anyone is bitching about Snokes lack of backstory is beyond me. How many antagonists actually get fleshed out backstories in these movies? Emperor? None till prequels. Vader? Prequels were made to show his backstory. Maul?

. Dooku?

. Grievous? GTFO. Kylo is the big bad of this trilogy, and he's getting the most backstory by far in the trilogy he's featured in.