Your assumption that the non US citizens always have the constitutional rights as citizens is mistaken. For example, someone on a travel visa can’t go and buy a gun and exercise the right to keep and bear arms. They also can’t vote.

They do enjoy First Amendment rights, so they won’t be jailed for speaking against the government. But if you’re not a citizen or a permanent resident, you’re a guest, and the host (US Government) can revoke your invitation (visa) and ask you to leave.

I personally don’t agree with Trump deporting people that speak up against Israel, but legally he might be within his right as President to do this.