Why is "argumentation" a resource for philosophical thinking?

When people argue about a  topic like equality, different ideas arouses and debates occur on varopus aspects of it. Different ideas are disscussed and loopholes are found, various ideas are combined and refined through this process.  The end product is a combination of refined ideas and most loopholes covered to give a fine law or statement.  

this headline suggests that midterm congressional   elections are at the corner and trump administration wants to activate his base by vowing to clamp down on immigrants and immigration as trump had said during his election campaign around two years ago. when a baby is born in usa, the baby becomes citizen of usa for 85 years and trump wants to end this rule of birthright citizenship to control illegal immigration and this what he said in an interview""we’re the only country in the world where a person comes in and has a baby, and the baby is essentially a citizen of the united states for 85 years, with all of those benefits,” "