Bitter lonely guys hate it when people try to empathize with them, more so than almost any other category of people. They often think that those who try to empathize with them are patronizing them, i.e. treating them as social inferiors. This is especially true when those trying to empathize are women, but also when they are "other nerdy guys."
The final phrase "other nerdy guys" shows that the author believes "bitter lonely guys" are always "nerdy guys." He presents no evidence for that, and in my opinion it is untrue. Many nerds are successful and happy, e.g. yours truly.
Student or Learner