Aggressive Betas are some of the most dangerous kinds of people in the world. Their frame is incredibly weak; they are the guys who go around looking to start a fight, especially against men who remind them of their own low SMV. They have years, sometimes even decades of experience being rejected by women in favor of Chad, but do not have the motivation, knowledge, desire, or intelligence to do what it takes to improve themselves to become Chad. The only way they can get pussy is either by paying for it (provision) or by committing violence against women who won't voluntarily give it up for them. Their poor looks, ignorance, weak social/financial status, and inability to get laid means they perceive themselves as basically having nothing to lose in the first place by getting their face fucked up, getting killed, or going to jail where their only option for a warm hole is another dude.
Post-wall women have seething contempt for young, beautiful women because they automatically lose to them in the competition for Chad's provision. This is because post-wall women truly cannot obtain higher SMV, no matter how hard they try. They cannot actually compete against pre-wall women in any way, so the only option left is that they necessarily must destroy the competition. You will not hear more intense slut shaming than the kind hurled at pre-wall women from post-wall women attempting to establish dominance in the female social matrix. Betas are even worse than them in this regard because men have far more control over their SMV than women do, so they have no excuse for being low SMV like post-wall women do. This is one of many reasons that women subconsciously recognize that beta males are lower on the totem pole than post-wall women (the social hierarchy being Alpha Males > Pre-Wall Women > Post-Wall Women > Beta Males > Children).
It naturally follows that since betas fall in between post-wall women and children on the social hierarchy, they tend to think less like men and more like post-wall women and children. Instead of rising to the challenge of competition by doing what it takes to improve their own SMV, they believe that instead their only option is to eliminate their competition: destroy Chad. Sometimes, Chad's mere high SMV presence is enough to provoke an aggressive beta to try to initiate a fight; other times, it's an imaginary perceived offense that Chad has committed against him such as "stealing" his oneitis. The latter is far more likely to provoke him than just about anything else.
Unlike the aggressive beta, Chad has a lot to lose by getting his face fucked up, going to jail, or getting killed. Women won't be attracted to his dentures from getting his teeth knocked out or the limp he walks with from getting his knee cap busted. He will not have access to his harem of women while he is in jail. His loaded bank account will be drained on medical bills, fines, legal fees, and his inability to get a job as a convicted felon. He will be evicted from his sweet bachelor pad and have to downgrade. Thus, the aggressive beta has succeeded in knocking Chad down on the social hierarchy.
Being muscular will act as a deterrent because people are way less likely to mess with a muscular dude. But even still, aggressive betas are a fact of life, and you will notice them more as your SMV improves. The only way to avoid letting them knock you down on the social hierarchy is by holding frame and refusing to engage them. If you have the choice, de-escalating a situation by leaving is almost always the superior option to fighting.
Unfortunately, sometimes a fight is still inevitable even when you don't start it, and for that you should be prepared by having some type of formal self-defense training. Do not be afraid to carry a gun and have formal concealed carry training as a last resort defense. And lift as if your life depended on it, because it does.