False equivalency: It's not just 'some random warrior,' it's the raid leader. It's literally the job of the raid leader to know all 8 classes, or at least have competent class officers that can green light it.
If you need to hide your spec to get into groups because you have some weirdass survival DPS spec, there's something wrong with your spec.
And for the record, when the armory was first introduced, nobody denied hybrid healers on the basis of their spec unless it was incredibly dumb, gear mattered more. That was just hybrids randomly freaking out.