Rephrased another way, relatively few voters actually (1) register and (2) vote in the party primaries. These registered voters apparently represent the "most p

Rephrased another way, relatively few voters actually (1) register and (2) vote in the party primaries. These registered voters apparently represent the "most politically involved" 10% of the overall population. (It's also somewhat misleading to include minors or non-citizen residents in the denominator when they aren't able to vote - it makes the result artificially small.) The primary system, while still susceptible to party insiders, is a lot more democratic than a system where political parties pick their candidates and say to the electorate "these are your choices, take it or leave it". (I won't address whether "more democratic" is a good thing, as that's a whole different can of worms.)