If Bob could actually fight he wouldn't carry around so much resentment towards his alleged "bullies". He would have kicked their asses and they would have stopped, end of story. And he would act completely different about it now and would have a very different set of advice for young people, more along the lines of tips for diet, exercise, and fighting instead of "Anybody to the right of Stalin is evil and must be killed for Social Justice and the Superior Future". And no, he didn't get bullied in high school and then learn to fight later. If he didn't learn to fight in high school, when the motivation to do so was at its highest, then he never learned. Period. This is real life, not some bullshit inspirational story of a guy who suddenly turns it all around. He's a lazy fat fucker, has always been a lazy fat fucker, and is only getting lazier as time goes on. And he's very likely an autist, who are notorious for their resistance to change.
Any aggression he may show in real life is not an indicator of fighting ability. It is an indicator of the attitude to pick a fight, which is completely different. Because of his size, and the fact that most people are pretty non-aggressive, he's been able to get away with it. If he's autistic, which I consider extremely likely, he is very likely to have nutrient absorption issues that slowed his childhood growth. But unless the issues were extremely severe, they'll keep on growing until they reach their genetically programmed height. My theory is that Bob was a runt through most of K-12 but eventually became the tall fat guy we know today and started throwing his weight around. He thinks that he lost fights then because he was small but can win fights now because he's big. If he ever gets in an actual fight, he is likely to very soon learn differently. I don't remember the guy who encountered him in real life saying how big he was either, so we don't know how aggressive he'll act towards someone else his height or bigger. I strongly suspect that he's a classic bully who felt victimized and now bullies those he thinks weaker while cowering before those he thinks stronger. But if he isn't, that's just more LOLs for us when eventually picks an obviously unwinnable fight and gets his clock cleaned.