It's easy to get confused because a lot of people who left England did so because they had no other prospects or no other choice, in the case of criminals or financial delinquents.
Reading up on the founding of the US is a doozy. Essentially, all the rejects of England sailed to the 'New World' because there was more opportunity for them there than at home.
It's called the "First Amendment," and you'll find it can be used to justify/unjustify all sorts of things depending on the current government in power.
First time studying American English?