"They provide a framework that enables wider engagement in the whole political process. Through these political parties, anyone who is an American citizen is able to run for office, and anyone can vote and express their preference for any one party."
Answer: Because they're scared of showing weakness
Explanation: Now this one may seem a bit out og the ball park but when I was in school, people just always stuck with a certain crowd. Everytime they weren't with the rest, their weaknesses would show.
Will you be my friend lol?
That's called a epic answer