That's BS. It's true: people do have different tastes and preferences, so opinions are just that. But it's not "superstition": different brands/blends of tea really do taste different, many times remarkably so. It's just like a McDonald's burger vs. a burger from a high-end restaurant. One of course isn't objectively better than the other (from a taste standpoint; I'm ignoring nutrition here), since it's a matter of opinion, but you will find that significant groups of people who like a particular food enough to have tried different varieties will usually form similar opinions, or at least sort themselves into different camps.

"Superstition" implies that the differences people taste are not real, and this is quite simply false. The differences are real; it's up to you which one you like better. More expensive doesn't always mean better-tasting.