Martial arts may be 'overused' in TG fiction, but they're hardly any less common in urban fantasy, epic fantasy, or sci-fi. And to be fair, far more people with a pagan background have martial arts training of some sort than you might realize. The main reasoning here is that most martial arts also involve a certain level of mental discipline, focus, and an awareness of subtle energy flows within and without the body. These things are absolutely critical for the serious pursuit of the esoteric, so there's a pretty high demographic overlap there. Additionally, as with GLBT folks, there's a certain amount of understanding that, as a pagan, you can and will be subject to defend yourself against bigots at some point or another. You can either go into said defense unprepared and willing to take a beating... hopefully only verbal, but unfortunately not always limited just to that; or you can go into ready to ensure your rear end isn't burnt at the stake along with the rest of your beliefs. Thus, combat training.

Not everyone who does the SCA / faire circuit is a pagan... but it's not very hard to find people who share your beliefs if you attend those events.

But you miss the part where the reason she slaps him is because he was groping her in the hallway. Even if he HAD purchased lunch and paid for the movie, that doesn't 'earn' him the right to touch her sexually. Especially in public, but really anywhere. There is no 'in story' description of the way the date went, but the 'meta' details go something like this:

They are expected to work together in teacher assigned groups on projects that require the students to meet outside of class. The three students on this project agree to meet at the mall's food court for a planning session. Two of them got food (on their own, paying for it themselves), the third (another guy who you do not see at all) did not. He stayed just long enough to have 'been there' before claiming prior arrangements and taking off, leaving the two alone to finish planning. At first she is worried that he's treating this too much like a date but they actually do get a lot accomplished and the project is coming together. So, when he DOES ask her out to a movie; she has no real reason to say no. But, being smart/safe about it; she agrees to meet him at the theater instead of having him pick her up.

The date at the theater is more traditional and yes, he does pay for the tickets. However, she buys her own drink. The date, unfortunately, goes badly. It's clear the guy has the wrong idea about movie dates... especially as a first date. The warning signs are there when he tried to get her to sit in the back. She heads that off by asking to sit down in the middle near other people, including a couple older people, with kids. Even still, she ends up having to fight off wandering hands through most of the movie. Afterwards, she thanks him for the evening and lets him know that his advances, especially on a first date, were inappropriate and unwanted. And leaves.

So, no... the slap is deserved. As is her opinion of him in general. However, you will notice that when she casts something to give him a little instant karma later on in the cafeteria... that things do not go as expected. Also 'meta' information that doesn't show up in the story... the boy is allergic to the dye in all that jello he is about to eat. It is the cause of his erratic behavior and ADHD like actions... and because of the way the teachers pull him aside and observe his emotional state; they discover both this problem and that he is simply acting the way his father acts around women. He is then put on a diet that avoids the dyes and other substances, works with a Big Brother style mentor, and puts his life back on track. He'll be encountered again, in book three... as one of the good guys.