If you post content like this you likely to get refused entering the US. I realize it doesn't apply to US citizens but it's also not like everyone can say what they want and get away with it.
You are taking this completely out of context, and if the OP had posted the above on x, or facebook they would not be denied entry. Threatening statements, glorifying violence, or ties to flagged groups is what gets you denied entry. And honestly, I agree with that.
If you are screaming death to america on your socials... I don't think i want you in America.