I'd probably chalk it up to AD, but out of curiousity now often do you use your cooldowns?
The more you hit shieldblock, especially at critical times like when taunting gormok or you're going to be taking a good deal of bleed damage using it it mitigate the additional incoming phsyical damage, the less your healers will complain about you. Your gearing/gemming choices seem good. I personally would only stick with the red gem in your BP and then go 30 stam in shoulders and helm, but it's not a huge deal.
I'd also say pick up a tanking weapon, even though yours is probably really good for threat (though I am kinda surprised you don't have mongoose on it if you're going for threat) and you don't technically NEED more stam/defense, it ALWAYS helps. Sorthalis is probably the easiest of the options you have to pick up. Maybe a Shiver or Blood and Glory or even a Quel'Serrar.
Spec/glyphs are solid, I personally prefer focused rage over shield spec, but if you're talking about reducing incomming damage then that is probably the way you want to go.
As far as minimizing damage in general: I'd defintiely say it may come down to playstyle. Pallies are really nice in that they both have more of mitigation from BV due to Holy Shield, and that AD is reactive. Warriors can shieldblock which ends up with us usually taking at least 20% if not far more depending on the boss (compared to AD below 35%) at any HP%, our Last Stand is very nice, but we have to use ours proactively rather than reactively, and unglyphed our shieldwall is more damage reduction, but in order to get it down to the same cooldown it's actually less. Also don't forget about enraged regen and armor pots.
Pallies have a lot of tricks up their sleeves, but if warriors are proactive about how they tank/when they use cooldowns to try and help healers at critical times (or even at any time just to help a little bit, warriors are very spiky damage takers sometimes) then warriors are just a good as paladins imo.
I'd agree also that a lot of it may be perception, or they may be trolling you =P.
Are you guys only using 2 tanks for H-NRB25? I would recommend 3 tanking it, using a 2-2-2 rotation. It makes phase 2 a lot easier too. With 2 tanks on whatever is being kited 1 tank can taunt off the first whenever they get bile then the first tank can go and clear poisons off without worrying about breathing the raid or getting to people in time. Also on acidmaw the second tank can taunt so that whoever removes the acid from the tank doesn't get breathed on. This in general just makes things a lot easier on healers.
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