Probably because if the End is enabled, someone is bound to find the portal to the End, enter it, make a faction there and block off the entrace to the end with Obsidian + Lava and claim it as his/her faction. Basically, his/her faction will be unraidable and it will not be fair to other factions. Idk, that's what I think.
I think he means for peaceful. But the end isn't forever it's just an island only a couple factions can claim it. Or claim it all. And then you have the ender dragon and all that and it would be to muh of a hassle.
I guess Enderpearls would Make a money maker then :p As said Unraidable and a ton of free obsidian :p
the reason why its probably disabled because it takes up some sort of memory the game has just for a small chunk of land that would've been trapped for good from an (going to be overpowered) faction and they could possibly receive an "income" of random items from the players foolish to go in, even if the portal and land was a warzone of some sort people would really only come to mine the obsidian which could be brought and mined on the overworld and make endermen farms which would be OP because of the xp rates, not to mention the memory. thats it, only strongholds, you could get craft mossy ones in the next update but not cracked ones, making them a pretty rare block even in the next update
strongholds can be pretty big, and there's 3 of them, i wouldn't be surprised if there was a local stronghold with unclaimed parts, who knows? there may be a faction secretly chipping away the stronghold nobody goes to....... the end may be disabled, but the eye of ender still points somewhere, the admins may have just deleted all the portal blocks.
Honestly, if we do add it factions would start to have huge advantages. Try making a base in the nether, I had a one unclaimed and it still has not been raided