But these folks represent the people in their districts, not everyone in the country (many of them need to keep this in mind), and if those people like the "Jewish Lobby" or the NRA, for example, they expect their representatives to support them.
If you can show evidence that there are a fair number of Representatives and Senators that support these groups depite the fact that their constituents, do not, then perhaps you might have a point about their having disproportionate influence.
As far as gerrymandering goes, both parties indulge in this practice. Faux outrage when the other guy's party if doing what your party would do if they had the power, is unbecoming.
Presumably a district that concentrates Republicans, leaves another with mainly Democrats. It doesn't seem as clever or sinister as many people think.