Bobby is entitled to his own work, and an aura of 'peevishness' is more than appropriate when faced with someone who is trying to dishonestly bully him out of it.
Adults don't get bullied, kids do. Adults don't complain about how they were bullied, it's pathetic to hear an adult say he was "bullied" by another same human being.
Do you think that Billy being muscular or confident or saying stuff is gay has a lot to do with the business dealings?
Author is stuck in high school.
Do you think that this sentence: “Haha, yea. I’ll say, ‘all I had to do was find a bunch of fucking nerds to build it.’” has anything to do with Billy's attitude towards engineers?
Quite possibly. It's also very possible that it was a knee-jerk reaction to the "joke" preceding it, impugning his character.