1.) It has an equal chance of dropping as any other spec's piece
That's actually a bit of a fallacy. While there is an equal chance of any single piece of gear for a class dropping (generally, there are 3-4 options: 1-2 DPS options, 1 potential healer option, 1 potential tank option), the chance of that piece of gear being useful for the spec in question is disproportionately against tanks for a very simple reason: most healer and DPS gear is largely interchangeable.
The *only* difference between a piece of gear explicitly intended for DPS or heals is that the DPS gear will (potentially) have accuracy on it while the healer gear will (potentially) have alacrity on it. This is even *less* important for moddable gear since you can just yank out the worthless acc/alac enhancement and replace it with whatever you need/want. The only gear where you can't do this and either have to eat the worthless secondary stat or pass it over is implants and ear piece. For *everything else*, DPS and healer gear is either *entirely* interchangeable (if there isn't any acc/alac on it) or is just *mostly* interchangeable.
Tank gear, on the other hand, is the exact *opposite*. The only thing a tank can salvage out of a piece of DPS or healer gear is the armoring. Non-tank ears and implants are entirely worthless to a tank.
As such, it's not entirely true that a piece of gear useful to a tank has the same chance as something useful for a DPS or healer to drop. Assuming you actually *get* the drop to be something appropriate for your class, tanks have a 1 in 3-4 chance of getting something that is even remotely useful to them whereas DPS and healers have the same chance of *not* getting something useful. It's for *this* reason that tanks have a harder time getting geared up (of course, the fact that tank commendation gear seems to be designed to be explicitly *worse* for said tanks than DPS/healer commendation gear *also* hurts): probability is *not* in their favor.
Gearing up my VG tank, I've run at least 20 FPs, killing both the bonus boss as well as the end boss. This constitutes at least 40 chances to get gear. I've gotten all of *5* pieces of tank gear to drop for me. And, sad but true, that's *better than average*. Unless you run with groups comprised of only a single base class, you're going to normally have a 25-33% chance of getting a piece of gear to drop for you. At best, you can expect to get one tank drop out of 9 times (1/3rd chance of class drop, 1/3rd chance of spec drop). At worst, on average, you can expect closer to one out of 16 (1/4tf chance of class drop, 1/4th chance of spec drop).
So, the next time you claim that tanks have the same chance of getting a piece of useful gear as anyone else in the group they're running with, I recommend you stick it up your tailpipe and smoke it. Unless you're running with people entirely comprised of your own class, you're going to have an explicitly and substantially *worse* chance of getting a piece of gear.