So true. Teaching children that a person who is being mean to you likes you sends the wrong message to both children involved.
But, especially at this age, it can be SO TRUE. Decades ago this boy might have been putting her pigtails in the inkwell. It might just be his way of getting her attention, but because he's just a little kid he doesn't know what the heck he is doing.
I've watched this awkward stuff between my son and a few girls that he's in classes with at the Y. They are all the same age (6), they make googly eyes at each other (the girls to him, him to the girls), and do odd things (nothing of the OP's post's level, but they aren't in *school* class with each other) to get each other to notice the other.
When I was K age, I took a cooking class with my mom, and there was a boy who, I learned from my mom later, adored me. He used to chase me around and around the class. I didn't have fun, I didn't really understand. One day he took a turn too fast, fell, and broke his collarbone. That stopped it.
As I got older, in retrospect there were lots of "I don't know what to do with my being" moments as I liked boys and boys liked me. I once accidentally hit a large bag of skittles out of a boy's hands when we were in 7th grade...I adored the boy, but my hands just went out of control, and the skittles went everywhere. And he was then angry with me. (about a year later he did something similarly brainless when he said a "joke" that was actually an incredibly inappropriate thing as he and some of our classmates came over to my house to work on a project, and my mom heard, aughhhh so he got embarrassed about that one)
I remember being older in elementary school and avoiding wearing a bra (that I needed) b/c the way that boys showed they liked you was to snap your bra. (also how girls tortured each other)
Would I want my son to snap a bra, accidentally knock a bag of candy out of a hand, chase a kid around the room? No. [Of course that middle one was an accident when I did it, hard to keep from happening (oh I'm still embarrassed about that moment).]
But I'd also hate to think that some brainless things he might do from an innocent place might get him into huge trouble when he's just barely started school. (if he were to keep it up, yep, trouble, but not at the beginning!)
If a girl were doing these things to my son, I'd prefer to get to the bottom of it, instead of rushing to punish the kid or say bad things about her.