Nobody was talking about OTing. Your main job as a tank is to take all the hits so the DPS and Healer don't die. DPS on top of that is a bonus, just like a healer being able to DPS is a bonus. You can easily keep hate even without STR accessories unless you are significantly less geared than your DPS or you aren't using your enmity combo frequently enough.
In static raids you only need enough VIT to survive a tank buster + an auto-attack so the healers can get you out of the danger zone. Gear and skill level vary greatly in DF content though so it's much better to err with caution and go VIT.
Somehow you don't get what squishy means. A tank with 40,000 HP is much less squishy than a tank with 10,000 HP because they can take more hits without dying. All defenses do is multiply your HP with regards to EHP. EHP is what matters and more HP means defense matters a helluva lot more because it gets multiplied by your defenses. You need a good combo of both defense and HP to not be considered squishy. And like I said, your tank DPS is trash for AoE compared to what healers can output.
Consider two tanks with the same amount of defense; they reduce all damage taken by 20%.
Tank 1 has 10,000 HP
Tank 2 has 12,000 HP.
The 20% Defense means their EHP is whatever their HP is x1.2
Tank 1 has 12,000 EHP
Tank 2 has 14,400 EHP.
Tank 1 can only take 12,000 HP raw damage whereas Tank 2 can take 14,400 raw damage.
Now let's see with low HP and high defense:
Tank 1 has 5000 HP and 20% damage reduction via defense
Tank 2 has 7000 HP and 0% damage reduction via defense
Tank 1 has 6000 EHP
Tank 2 has 7000 EHP
Tank 2 is still less squishy than Tank 1 when they have 0 defense because their HP is higher. Tank 1 will need 40% more defense (or enough defense to mitigate 40% more damage than Tank 2) to reach the same EHP as Tank 2 just because of raw HP difference.
That's why WAR and PLD are as good as each other at taking hits even though PLD has higher defense and WAR has way higher HP. Their EHP is about equal.