There are only 160mil valid passports in America right now.
You are right though that you can be a registrerede voter with no party affiliation, but there are still 50mil eligible voters that haven't registrered.
And do you deny that a lot of Americans have a hard time getting off of work to go vote? That making election day a national holiday would not easily make a lot more people participate in the countrys democracy?
You got here because american class solidarity is weak and easily divided. You got here because you didn't fight the corrupt bastards in your government. You got here because you let fascism brew in the background and grow stronger.
Voting for status quo is a better starting point than letting fascists take over, fighting them, and in the lucky case of victory being able to rebuild.
Not voting for status quo when the alternative is fascism, is equal to a vote for fascism.