Indeed - but the refits of British ones improved that survivability. Damage control was no less critical for carriers of all types than it was for other warships. By the time the Americans entered the war the Royal Navy already had considerable experience of ships being damaged in action and ways in which they could be made more survivable.
limited effect, see also the Light Fleets intended to replace the Lend Lease ‘Woolworths carriers’, specifically designed as ‘disposable warships’ to be scrapped at wars end or if they sustained any notable damage..
they were merchant standard hulls too. A bit extra subdivisions to improve survivability, and lots of empty oil drums in empty compartments to provide buoyancy if the war got in.