No country on Earth affords equal rights to citizens and non-citizens. If this "terrifies" you, I encourage you to reflect on your fears and whether some of them may be disproportionate to reality.
Others are only for citizens (and EU citizens, but via a strange legal method), but the most fundamental ones state "Everyone", not "every citizen".
Smart move. :-)
Not having basic protections for non-citizens would be rather worrying, but let's not act like the mere existence of a difference is worth freaking out about.
EDIT: To be clear, I'm not suggesting that Justice Thomas's concurrence not providing these protections to non-citizens would be a good thing. I'm just saying that 'non-citizens should have the same rights as citizens' isn't a position held by any country on the planet.
In my opinion, not having your property taken unfairly by the police is more of a basic right everyone should enjoy, rather than a special right afforded to citizens like voting.
That's fine, but affording no rights to non-citizens would be highly problematic. Some argue the Constitution doesn't protect the rights of illegal immigrants, for example, but it makes clear distinctions by using "persons" in some spots and "citizens" in others.
Persons have a right to due process. Citizens have a right to vote. The difference is very important.
The average ruling in a single minor case today is longer than the entire Constitution.
Which is why we have the status quo: the vast majority of rights enjoyed my U.S. citizens and residents are enjoyed by aliens, with some discretion.
"... The panel affirmed a conviction for possessing a firearm while being an alien unlawfully in the United States in violation of 18 U.S.C. § 922(g)(5)(A)."
http://cdn.ca9.uscourts.gov/datastore/opinions/2019/01/08/15...