That is not true. There was no gearscore yet back in tbc, but ppl did inspect you and judge you by the gear you were wearing. I was in a non raidng social guild back then, and I did a lot of BG and got the pvp set for tanking as a bear back then, because that was the best I could get at that time. What do you think what I got to hear a lot of times in Pugs? “OMG YOU NOOB! You can´t wear pvp gear in pve.” Well I did what I still do today, if I can´t find a group, I make my own. Helps if you have friends and guildies.
And then thinking of all the attunements you needed to be able to even access all the content… very inclusive…