It is the same thing because if a tank can hold hate with only flash then why do they need to use the aggro combo? The aggro combo may be part of the tanking kit, but if you can hold hate without it then it is objectively not required so why would you need to use it if a tank's job is only to tank? For dungeon trash pulls AoE Flash hate is technically more important than combos anyway especially if the DPS are using AoE damage.
I don't know how else to get you to understand this so I am going to be really over the top descriptive here.
A tank's job is to tank therefore it only requires holding hate and using mitigation; if holding hate can be accomplished by an easy one button press of Flash until I run out of MP then why do I need to waste energy doing combos? If DPS isn't a healer's job then DPS isn't a tank's job either so if I can keep hate while doing 0 DPS then why would I try harder and have to press more buttons just to do DPS? It's not a tank's job to do DPS so if I can ignore it and still do my tanking job then it is totally fine.
It's all about double standards which I already mentioned to you.
If someone makes the argument that a healer is only required to heal (which is the statement made by the poster I initially responded to on this subject) then by that logic a tank's job is only to tank therefore if you have an issue with how a tank plays doing 0 DPS and only using flash and mitigation that is pure hypocrisy.
If it is acceptable for a healer to do 0 DPS since DPS is not their job then automatically a tank doing 0 DPS must be acceptable as well since DPS isn't their job either. Only DPS jobs have to DPS. I realize PLD is the only tank that can actually do this while keeping hate in dungeons since Flash does 0 DPS, but it still means that if you believe that healers are okay to do 0 DPS then you cannot have an issue with a PLD doing 0 DPS either because like I said double standards and hypocrisy.
I don't know why you think this is a bad argument. It is literally a mirror image to a healer claiming they don't DPS because "a healer's job is only to heal so it is okay if I do 0 DPS". Instead it is a tank saying "a tank's job is only to tank so it is okay if I do 0 DPS." It is literally the exact same mirrored mentality.
I am sorry to be so blunt about all of this. I am not trying to be mean or rude to anyone who doesn't DPS on healer. I am just trying to explain objectively why this mentality is just wrong. It just doesn't work in this game due to how it is designed. Healers are not pure healers because the healing needed is just too low to need to dedicate all your GCDs to healing and you have plenty of opportunities to just DPS some. Doesn't matter if it is a lot, it is all about just putting a bit of effort into tossing some damage here and there. If the tank is bad, or under geared and therefore squishy then np, but in groups where there is a lot of downtime between healing then most players should have time to just throw a little bit of damage.
If a healer is literally not skilled enough to do DPS and will cause deaths or new to the fight then fine, but simply using "a healer's only job is to heal" as an excuse not to DPS on healer is just silly. This is highlighted by my silly tank parallel.