You're right but I think you're running into the emotional side of the issue for some folks. The "not coming back" angle is a feature not a bug. Saves having to track folks down, potentially detain them, etc.
People haven't always complained about this feature/bug/whatever because the US has generally not had people in charge who allow in people charged with sex trafficking (like the Tate brothers) but stop and harass even American citizens who are accused of saying mean things about Israel on the Internet.