It's also important to understand that entry into the US is not a right for non-citizens and suspicion is generally enough reason to kick someone out at the bor

It's also important to understand that entry into the US is not a right for non-citizens and suspicion is generally enough reason to kick someone out at the border. I don't think its fair, but traveling to another country you're not a citizen of you have no reason to expect fairness. We don't expect free access to other sovereign countries. For instance, and China has a long history of kicking out foreigners for arbitrary reasons, targeting foreign bars for random drug testing, etc, and this is considered acceptable because that's the law there. Here, we don't target foreigners/outsiders (laowai) so harshly. We treat foreigners way more kindly than most countries. We still give out tons of visas every year to allow people various opportunities. What the CBP can and can not do is also dictated by law as a security mandate. The law says people can be denied entry for a variety of reasons. Until we know those reasons, if we can possibly tell those reasons, there isn't much to say.