Linehan was arrested for making this post:

> If a trans-identified male is in a female-only space, he is committing a violent, abusive act. Make a scene, call the cops and if all else fails, punch him in the balls

This seems like a straightforward call to violence to me. And he was released after police ascertained that he had no intent to act on these statements.

If someone made posts along the lines of "Christians are abusive, punch them" would it be surprising if CBP took them aside for further questioning?

The other context is also that Linehan was awaiting trial for harassment and criminal damage against a 17 year old transperson at the time. And that he ultimately didn't get charged for the tweets, and did get friends in high places to whinge at the police on his behalf

CBP, maybe not - there’s a lot more leeway for things that happen at the border, for better or worse.

But in general US law sets a high bar for claims of incitement. Your hypothetical statement would certainly be considered protected speech. That is, of course, not to say that you would not be a victim of vindictive prosecution ;)

yes, actually, it would be suprising if CBP took them aside for further questioning. That's not really how it's "supposed" to work.