Our Constitution and Bill of Rights is framed in terms of recognizing independent-existing natural inalienable rights. Citizenship is a complete red herring. The SC has been writing justifications for blatant infringement of natural rights for decades, even before the current neofascist takeover. Take the Bill of Rights as a list of test cases, run down them, and try to find one that is actually passing.
Reno v. American-Arab Antidiscrimination Committee made it clear that there are no First amendment protections from deportation. This is well established case law for decades now.
https://www.aclu.org/documents/reno-v-adc
This is why talking confidently about things you have absolutely no idea about makes you look foolish.
Pragmatically, yes, Khalil will likely be deported due to having exercised his freedom of speech. This, along with many other current affairs, should be abhorrent to anybody who actually believes in the ideals of individual liberty - regardless of the justifications crafted by the judicial, executive, and fourth estate. And I really don't know what you gain by cheerleading authoritarianism, besides some feeling of smugness of being on the winning team.