"如果我们的开国元勋希望我们关心世界其他地方，他们就不会宣布从中独立出来。"

Simplified Meaning:

The quote is saying that if the people who started the United States wanted us to focus on other countries, they wouldn't have made America independent. It's like saying if you started a new bakery because you didn't like how others were baking bread, it means you wanted to do things your own way. In this view, they created a new country to make their own rules and decisions instead of following what other countries were doing. It suggests that America's founders wanted people to focus on making their own country better, rather than worrying too much about issues in other countries. For example, think about someone who decides to live on their own because they want control over their own life and decisions. They probably did that because they believe their own ways are better for them, rather than trying to manage someone else's life. This idea can help people understand that focusing on improving your own situation can sometimes be more important than getting involved in the problems of others.