Quote Originally Posted by Max_Killjoy View Post
This comes across as another case of intentional vagueness (in 5e, not by you), of trying to eat their cake and have it too. Alignment is descriptive... until it's not.
5e alignment is ALWAYS descriptive.

Quote Originally Posted by Max_Killjoy View Post
PC alighment is "these actions are typically...", but then there are also planes, places, energies, and entities that are objective inherently Good, Evil, Lawful, Chaotic, etc.
Those things are not arbitrarily "objectively inherently Good, Evil, Lawful, Chaotic, etc". They inherently have the traits that fits the description of a given alignment, because they are created by those traits.

See Gehenna :
Gehenna is the plane of suspicion and greed. It is the birthplace of the yugoloths, which dwell here in great numbers. A volcanic mountain dominates each of the four layers of Gehenna, and lesser volcanic earth bergs drift in the air and smash into the greater mountains. The rocky slopes of the plane make movement here difficult and dangerous. The ground inclines at least 45 degrees almost everywhere. In places, steep cliffs and deep canyons present more challenging obstacles. Hazards include volcanic fissures that vent noxious fumes or searing flames. Gehenna has no room for mercy or compassion. The fiends living here are among the greediest and most selfish in all the multiverse.

OPTIONAL RULE: CRUEL HINDRANCE The plane's cruel nature makes it difficult for visitors to help one another. Whenever a visitor casts a spell with a beneficial effect, including a spell that restores hit points or removes a condition, the caster must first make a DC 10 Charisma saving throw. On a failed save, the spell fails, the spell slot is expended, and the action is wasted
Gehenna isn't objectively Neutral Evil because some cosmic forces wrote "NE" on it. It the physical representation of a specific kind of mental and spiritual traits, namely suspicion and greed, which often leads people to behave like the 5e description of the neutral evil alignment. Its inhabitants consistently behave in a way that fits the description of neutral evil, and the plane influence everyone that is there to make helping others less effective, making them more likely to behave greedily and suspiciously.

If someone removed greed and suspicion from the souls and minds of all who exist, Gehenna would disappear, because it would have nothing to be the representation of.

Similarly, devils are created from the souls of people whose behavior could be described as "methodically tak[ing] what they want, within the limits of a code of tradition, loyalty, or order." The souls have any trace of personality and memory erased, except for a faint remains of in which way they did those things, and the new being is basically nothing but tendencies to take what they want within the limits of the code, until it develops new experiences and intellect which will grant it a new personality and memories. If it REALLY wanted, a devil could stop behaving that way. But most don't, because they enjoy taking what they want within the limits of the code and being themselves, and a devil that stops behaving that ways stops being a devil. Quite literally, it's the way they act that makes them be incarnations of lawful evilness.

There is no instance in 5e of "they are X alignment" without "they do X things that fit the description of the alignment".