Two problems I have with this.
1. Not everyone is so nonchalant as you about it.
2. and this one is the biggest... many players, especially new ones... are still learning. If they see that this is how it's done, you will find them still doing it at 55 and they'll be like "What? NObody's ever had a problem with it before, what's your problem?" I seriously find this all the time at 50-55 (50 pre expansion).
3. Follow up to #2, this is also why I find even at 55 tanks in full dps gear thinking they can tank cause they did it before and nobody told them how to properly tank cause "oh it's leveling up it's easy mode"
1. I call it realistic rather than nonchalant
2. Fair point, and I don't actually need on it if I'm in a situation like that myself (just not worth the potential drama), but I see the logic in it so unlike any other case of needing on other classes gear I don't call them out on it.
3. While that's true, I'm not gonna cut my leveling speed down to a crawl by gearing with mitigation at low level just in the hopes that some won't do it at high level, especially since I generally spec dps instead while questing and PVPing, and I'm not gonna demand that someone else does either. I leveled my first 50 as a tank and with mitigation gear and know how slow it is, I'm not doing it again.
So, I queued up on my operative healer and got HM czerka meltdown. Zone in and discover to my abject horror that *I* am the tank!
I doubled checked my queued roles and verified that it was set to healer (as I have to reason to ever change it, especially not to tank, lol). So I was at a loss, and quite embarrassed as everyone was rightfully pissed. I say my apologies and quit the group.
Still have no idea what happened. But I was the weird one for once.
You should definitely report that, strange bug. I've seen people claiming GF put them in a role they didn't queue for before, but it was always been a role they could potentially fill if they specced for it..