"Somebody", indeed, lol.
And, well, my point was that you can CAPTURE cities even with tons of units in them.
I never said you could KEEP them easily, lol.
Also, what do you mean "even if you capture the LAST city"?
Like, why would you play with "you need to kill ALL units to kill the CIV" to begin with?
It's just ANNOYING (now with HIDDEN units even more so, but it was stupid even back then with normal units, when a random spy could hide in a different civ city as well), lol.
This option is good for themed and roleplaying scenarios (like, using a Hero to roam around without a city), but it's total nuisance for any normal game.