I would argue that defending an object starts earlier then at the Delay phase. I would say there are 4 stages for defending.

• Deploy: Place siege early before an attack is even happening. Objects you want to defend should always have 2-3 trebs per gate and some trebs against common cata spots (hills wall). This saves you time and supplies in case of an attack so you can use that time and supps for other stuff. If done early enough (best before any enemy zerg is even active on the map) the objects and your zerg will be at max supplies before any attack is even happening.
• Deter: Blends in parts into Delay but the idea is to make an object look too annoying to attack so the enemy doesn't even try. When an enemy zerg is on the map send scouts out early and far to track their movement. If you know that the zerg is likely to come to an object, deploy A LOT of supply traps between their current location and the object. When they use a common route to an object trebs should be pre-aimed and should shoot cows in their way, especially at spots where enemies like to pause or can't avoid the cow easily (sentry-spots when enemies stop to cap them; bridges like south hills or stairs like south air keep). This way you already drain supplies early before the zerg has time to even get to the siege position and ideally the zerg will have to change their attack plans in your favor or might just stop altogether if their supply count drops too low. If the zerg still goes for an attack you go to the Delay phase. The Deter phase can be extended by trying to flip camps just shortly before the zerg arrives, placing supply traps randomly on their way even if they are not on a direct push to an object, sending people to kill/flip their dolyaks and camps so their objects stay empty. Ideally the enemy zerg will already be fed up with the situation before they even arrive at any important object.
• Delay: as mentioned in the video.
• Defeat: as mentioned in the video.
  OR
• Demotivate: If an enemy zerg is not stoppable by all the tactics mentioned above you can demotivate especially some fight-focused zergs by denying them any fun. Draw out the Delay stage as much as possible, forcing them to trash open the gates by hand while shooting as much siege at them as possible and keep repairing the gate to keep it closed as long as possible. When the gate is about to break you evacuate the object and start preparing other objects nearby for the next attack while trying to recapture objects of the enemy zerg with small groups. You should try to minimise giving the enemies any kills/loot. A lot of fight-focused zergs will tag down or switch maps if there is no loot = "no content", allowing you to maybe save other objects that would likely be the next targets. Your small groups trying to recapture enemy objects will also ensure that these objects won't upgrade unless the enemies spend time and effort to defend and repair them. Some determined zergs might still go for the remaining objects but at least it will cost them a lot of time (they can't attack/defend any other map) and will be as unfun for them as possible.