Sure, it isn't an absolute effect, I could have phrased that better. I think it's pretty clearly a directional effect that safer districts pick their representatives in the primary (which often have a candidate backed by the institutional power structure).
But that just reflects the fact that a given party has overwhelming support in those districts. It doesn't mean that the result is unrepresentative. So Phila. and NYC pick their mayors in the Democratic Party primary. The result isn't unrepresentative - there was no question that the mayor was going to be a Democrat.
Yeah, I'm not arguing that it isn't representative, I'm arguing that we shouldn't design for that outcome, because it shifts power in the direction of the party and away from the constituents (and it does so even in districts where the constituents are largely comfortable with the resulting representative).
