I think the difference is whether it is required or not.
Hunts can sometimes be soloed. Back when the Elpis maps hit, our Elpis A ranks were constantly dead since several of the map spawns were near them, leading to them getting killed outside of train schedules. You don't need a coordinated and skilled group to kill hunt marks. Organization there is optional.
Now, clear GolbEx with both healer 2 man circle partners dying all the time so both healers are constantly killed in Gales 2 and Gales 3 and the meteor shower mechanics (I think both of those also have the 2 man circles) so that your healers are constantly killed with no way to save themselves. How's do you get the clear?
Oh, you abandon that group and start another? Or have to grab some friends? Or get people on voice comms? Or keep adjusting your PF requirements? Or get people who have already cleared it to carry you? Or only run it in the first week or two to get your clear before all the HARDCORE PLAYERS have got their clears and stop running it in parties still trying to get their clears?
Yeah, that kinda makes it hardcore content.
While it very much is true that the definitions of content are different, an encounter with around half a dozen body checks, a lot of overlapping mechanics, and some mechanics that give you ~+/-2 sec to get into position before you WILL die, and has several of these during the encounter, often following (or concurrent with) body checks that WILL wipe the party if anyone is out of position or dead? Yeah, that's not "midcore".
ZodEx is midcore, possibly on the easier end of it (IF you have a good danger dorito; if not, snakes eat people for lunch).
HydEx is midcore.
GolbEx is NOT midcore. Anyone who thinks it is is a hardcore player and doesn't realize it/doesn't realize how out of touch their definition of midcore is.
Mhm, this.
Most of the Coil fights are easier than their modern same-number (of 12) fights in current content, with few exceptions. There are some that were substantially harder, and more akin to current, but there were a looooot that were far easier. As you say, P1S's mechanics would have blown people's mind if that had been 1Coil.
So is GolbEx. So that's not really saying much. They're still apples-to-apples easier than present content.