I find there's no difference between the tea I drink in teabags or loose. I even cut open a teabag to inspect it and visually it's the same stuff.
Yorkshire tea, Tetley's etc are all just blends of tea. The same as most teas. If you happen to find you particularly like them then I don't see why people have a problem with it.
Perhaps it's the same way with whisky purists. You know the people who wax lyrical about how they like a particular obscure single malt, and pour scorn on anyone who drinks Bells or puts coke in it?
Why someone should be mortally offended by what someone else drinks is beyond me. The only way that it's in any way acceptable is if someone is trying to help someone get more enjoyment from it, most of the time it just comes off as someone trying to look refined.