There was a lot of BS floating around from the hardcore private server bros in the leadup to Classic launch. People turning down bear druid tanks while leveing. Seen people looking for an SM tank "only prot spec".
I'm not gonna discount what you saw, but I never once saw this when I was levelling my druid tank. In fact, I saw the exact opposite. All of the private server veterans I ran into were preaching fury tanking. Deep prot seems like it fell out of favor with that crowd a long time ago. Far more people were saying prot was unnecessary even before launch day. I suspect the people who demanded prot spec warriors were people frustrated by playing with bad tanks who misunderstood the fury tank idea and were trying to dual wield in berserker stance at level 30.
I mean fair. It's anecdotal. And I'm sure that person was probably new to Classic/vanilla and they've learned since then. Which I guess is understandable because for much of the game's life, if you are a tank, you're a prot warrior. if you're healing, you're going to have to be a holy priest, or whatever.
And yeah, some words carry certain perceptions. Like a fury tank and the dual wield. Same thing when you say 2h dps warrior, some people think you mean Arms. And it comes down to person-by-person. I refuse to call a 31/0/20 mage an arcane mage. You only use Frostbolt and you rely on the PvE oriented talents in frost most of all. Some people do call it an arcane mage. There's always an element of a single person's reference point.