Most likely that senator is from a net-taker state like kentucky or arkansas, one that would be bankrupt without california and new york overpaying the fed to subsidize poor republican states.
There is also more affluence in California and the Northeast vs Middle America. Regardless of politics Middle America is not going to be granted the same economic opportunities as coastal regions.
Because we live in a Union? The idea is that your state will be helped if the table is ever turned. Not everyone in Kentucky hates California and the people who live there. What you're essentially promoting is reducing the role of federal government, which is the same thing current Kentucky senators want. I'm sorry to be so blunt but to be honest your comment sounds hateful and ignorant.
Why stop at taxes? Let’s talk about water, why should all these states be subsidizing California’s water use? Why aren’t they bootstrapping desalination plants? Quit mooching.