Enjoyment is in absolutely no way a necessary condition for bullying. Bullying is abusive treatment, often directed repeatedly at specific individuals. That's what was happening here. "You know, every time I see a comment from [a specific Thunderbird developer] I just want to reach out through the intertubes and cut off his damned fingers to prevent him ever writing any code" That is about as clear a case of bullying I've seen in the 13 years I've been involved in Mozilla.
You can make all the excuses you want for him, and you can re-define bullying if you like, but he has gone well beyond "not seeing the need to spare people's feelings" here. He has verbally attacked people and he thinks he can get away with it because of his hacker credibility. "Because I'm a great programmer and you're a nobody programmer, I can call you names and tell you to die die die and tell you I'd like to cut off your fingers so you can't code any more. That's about as crisp a case of bullying as I can think of.
You can make all the excuses you want for him, and you can re-define bullying if you like, but he has gone well beyond "not seeing the need to spare people's feelings" here. He has verbally attacked people and he thinks he can get away with it because of his hacker credibility. "Because I'm a great programmer and you're a nobody programmer, I can call you names and tell you to die die die and tell you I'd like to cut off your fingers so you can't code any more. That's about as crisp a case of bullying as I can think of.