Question

What is similar about why congress and the courts informally change the constitution ?

Answer 1

This process is somewhat similar because in fact these to bodies are not really "changing" the Constitution at all--they're simply finding ways to make or interpret laws that can fit inside the "shadows" of the Constitution. 

Answer 2

To make it better fit the needs of the party and make everything run.

Agenda's, ideology, progressivism, and what their essence faiths are about our nations independence, checks, and balances, residents independence, power. I think fear has a lot to do with it. Forced into voting a certain way, to support the party in office philosophy, or else.. learned ostracism, ridicule, etc. Money. Greed.