Its hard to tell what personality type was what when you look back into the high school days. Perhaps I am being ignorant, but I dont think INTPs would see the point. As an ISTP Im more the I'll get them when the bell rings type, or when they are at their weakest position. I could never SEE an INTP picking on someone. An ISTP perhaps, but only to see what its like. ESTJs and ENTJs seem a lot more likely to dwell in such territory. Especially ESTJs, an immature one without control at home or other places would perhaps search to control each others emotions. Whats more controlling, intimidating or pleasing someone? Intimidation is a method towards a control.
Just looking back, I would look for the weakest time, hardly in class.
If the ISTP was the opposite sex they couldve been trying to actually get you (as twisted as it sounds). Maybe they were just trying to be your friend. The bottom line is we definitely do not get people's feelings and how to evoke certain emotions. We may try the opposite of what a normal person would do to achieve an end, especially at a younger age when we are still learning how people react to different things.
Couldve been an ISTP picking on you, I just doubt it. I definitely agree that an ISTP coined the term nothing is unconditional. With that said I dont dismiss the possiblity.