The uselessness of partisanship

Partisanship is like...

...calling the plumber to fix any problem in the house just because you
had good luck with the plumber once in the past. Sensible people call
on the person with the appropriate skills for a specific job. If there
is an electric problem, do you call a plumber? Of course not.
Similarly, why would someone apply the same solution regardless of what
the problem is? Would you apply the brakes any time you needed to do
something to correct the velocity of a car? Of course not. You apply
brakes, accelerator or steering inputs to guide the car where you want
it to go.

Why do some people try to apply the same conservative or liberal
solutions to every situation? It makes no sense.