We have been trained well.
Party leadership down to the run-of-the-mill members, those in the local trenches working for their parties, work hard to get their candidates elected. It is a matter of honor as well as a labor of love to give of your efforts, time and money, so that their person gets elected. There is a cost for this, and that cost is independence, freedom, liberty. The cost is the same for either party you tend to support, Democrat or Republican.
Both major parties look to suppress some liberties, whether it is to own a gun or to control one's own body. Same tyranny, different facts; there is no real difference. Why don't voters see this? If they did, we would not have the mess we have today, the long, long, long term representatives and senators, forever delegates, and officials who treat the public treasury as their personal wallet.
It is comforting to have parents to lean on, to think for us, to coddle us, but at some point we must grow up and think for ourselves, to see that those who control us do it for their good, not ours.