"Corporations are people" if the corporation is the State, it seems.
Michael Badnarik gave a good presentation on the subject:
In Spanish there's that "real" too (as in "derechos reales", "real estate taxes"), that makes it third meaning after "real" and "royal".
This explanation makes more sense to me intuitively, as there is a lot of material stuff that is not "real estate", in fact majority of stuff that is material is not real estate.
The funny thing about the link you share is that the two comments that offer the real answer are the least voted.
They explain why actions were called in rem (a demand related to possesions as opposed to in personam) and that real estate is refered to goods that you can't move, as opposed to furniture. Actually in Spanish real estate is "inmueble" while furniture is "mueble".
Let's not forget that for land in many countries, if a squatter uses your lad for xx years without being challenged, it is theirs. So it's recognized as different.
"With the exception of oil, gas, coal, gold and silver, the state does not own mineral rights in the UK. Generally minerals are held in private ownership, and information on mineral rights, where available, is held by the Land Registry together with details of land surface ownership."
https://www.bgs.ac.uk/mineralsuk/planning/legislation/minera...