Here's another simple way to put it: if politicians only focused on what you call "minor things we disagree on", voters can simply and easily vote them out. But voters don't think those are minor issues, it's just that you don't personally value them. Abortion, for example, is hardly a "minor" issue, for many it's a matter of life and death. You may think marijuana is a "minor" issue, but for others it's a critical crossroads that will determine the future of their community and country.

Politicians don't have mind control powers, there is no mechanism to make voters "hyper focus" on issues that voters themselves consider minor. If voters focus on something, it's not minor to them. All you're saying when you dismiss these politicians' focus as "minor things" is that you either don't know or don't respect the decisions of the voters they represent.