I'm a total economics nerd and a politics junkie. One thing that really gets under my skin is when I make a comment about something related to those two interests and someone acts surprised or expresses some kind of disbelief that I would actually have something intellectual to say. Why does that always seem to happen to me?! UGH! :steam:
To be honest, I'm kind of shocked myself.
That is definitely not the kind of thing I'd expect from an ESFP. This is the shock of being impressed, not of being bothered, though.

I guess you're a real-life example of
this.
It's just that, well... when you see a goofy party girl type being all silly and fun and self-indulgent... you kind of assume she's a ditz. Mostly because a fun, indiscriminate, goofy, self-indulgent ditz is considered the foil to the ascetic, solitary, perceptive, intellectual in literature. Those are the two archetypes in people's minds, with or without MBTI.
Part of the reason such people are considered ditzes is because they enjoy "shallow" or "cheap" fun, rather than "sophisticated" fun. There's also the idea that their judgment is impaired in some way because they tend to judge people and events superficially, like by what they wear, their hair, the convenience or immediate fun of it, etc, rather than their character or symbolic meaning.
People often make the mistake of assuming that temperament and character are related to aptitude and interest in particular arenas.
The two interests you described, for instance... go completely against your temperament. They're the sort of thing people expect NTs to be interested in.