• We have updated our Community Code of Conduct. Please read through the new rules for the forum that are an integral part of Paradox Interactive’s User Agreement.
On the other hand, that's how Summerhall is treated, so there is precedent.

I believe that summerhall is another case altogether. That ruin wasn't restored due to the sorrow and memories it brought to the ruling House of the Iron Throne. The Reynes were annihilated because they were rebellious. Just because you detest the people living there doesn't mean you have to feel the same way about the piece of land they inhabited
 
Summerhall got burned down by accident,

Castamere got blown up for a reason.
 
I believe that summerhall is another case altogether. That ruin wasn't restored due to the sorrow and memories it brought to the ruling House of the Iron Throne. The Reynes were annihilated because they were rebellious. Just because you detest the people living there doesn't mean you have to feel the same way about the piece of land they inhabited
Summerhall got burned down by accident,

Castamere got blown up for a reason.

I believe he was referring to the fact that Summerhall is, in game, a ruin right smack in the middle of Westeros. Not that the in-universe reasons for its destruction was the same.
 
Yet summerhall is truly a ruin, it's completly burned down,

Castamere just has water in its tunnel... aaand some dead bodies.
 
A "castle" holding in CK2 doesn't necessarily represent just the castle, but a barony or county that is overall structured administratively as a set of farms and homesteads governed from a central, fortified position. Having it as a ruin would mean that the entire stretch of land has been abandoned - somewhat possible in Summerhall's case, definitely the case with the Essos ruins - and is of no value to anyone.

Castamere, though, is essentially what would today be military occupation - it's directly controlled by the Lannisters and doesn't need a central castle, even though the basic walls for one still exist. If the Lannisters decide to grant it to someone, the remains of the castle are possibly easy enough to restore to serve as a rudimentary seat, and possibly are still better than a simple tower or keep as most poorer counties have.