Until I know what Khalil did or said to warrant his treatment, I can't make a judgment.
You would be well served not to make hasty judgments.
When any student calls for revolution or intifada, they deserve to be expelled. You don't get to call for armed uprisings and expect to keep your visa or anything you've earned at that school. When your words lead to the mistreatment of another ethnic group, or in the case of that couple in DC, murder, your rights to say those words should be curtailed and you severely punished under maximum penalty of law.
Free speech has limits, very far outer limits, but limits nonetheless. Sentiment spreads like a contagion, and when it reaches one unable to withstand the urge to act on it, you see what happens in DC.