2. Which means that there is generally no policy that makes everyone happy. So you need a party with a program that aims at finding compromises that are acceptable for everyone.
3. But nobody will vote for such a party. Why would you vote for a party that gives you 50 % of what you want if there is a different party that is more aligned with your views and preferences and promises to give you 90 % of what you want?
4. In consequence the political direction tends to hop between extremes instead of settling on compromises. One group gets really unhappy with the current situation, shows up for elections, votes their party into power, moves the situation into the direction of a different extreme, until others get unhappy enough to start the process all over again.
5. Even in political systems where [sometimes] a coalition of parties exercises the power and they are forced to compromise, the outcome is all but ideal. Things move slowly because finding compromises is hard if you do not really want to compromise. Voters look down on the party they voted for because they are not delivering what they promised but only compromises.
I guess the moral of the story is that the voters have to realize that their view is not the only valid one and that voting for compromises would probably yield better outcomes than voting for extremes and either going in that direction for some time until turning around or maybe arriving at a forced compromise that no one voted for.
[1] Exercise for the reader, find something politically relevant that does not depend on perspective and personal preferences.