I don't think it's that. Some people are legitimately obnoxious and believe they can dominate you because they spend more time lifting weights, and they have really obnoxious philosophies and pet theories that justify their own behavior. They're the natural enemy of shier people, and as a result those types can be distrustful.
Lifting and in general working on yourself does shift your world view. You start to see through a lot of the bullshit that people peddle during the day. I bet same thing happens when you build something all by yourself knowing that only you could have done what you did.
Well, very broadly speaking there are two ways of looking at things. One philosophy is we should live in a world where the playing field is leveled and we should look out for the weak.
Another is the weak need to get out of the way of the strong, and if you are struggling, it is your responsibility to become stronger.
Increasingly I feel personal philosophies are largely self-serving. You believe in things that will benefit you. As you gain strength in one area, you tend more towards the second philosophy.
However, I think believing that can easily turn people into bullies. Do we want a society that is optimized for the dominance of the few? Do we want to break every interaction down crudely into a competition between "the strong" and "the weak," despite the fact that human beings are complicated and are strong and weak in many different areas?
The mistake a lot of meatheads make is assuming because they have physical strength, they should be allowed to dominate. However, in modern society, I feel other forms of strength are much more important. Emotional strength. Moral strength. Intellectual strength. They don't have much to do with muscle size, despite what some seem to believe. We should respect character more and physical appearance less.
I'm actually gaining weight pretty quickly now after weight lifting, but I hope I never forget what it feels like to be pushed around, and I never let myself push around others.
Obviously society would be better with more winners, but what we need to aim for is equal opportunities not equal outcome.
As for modern society, there are many ways to view what is important and in what way. Questions like who is benefiting the most from these new masculinity rules (toxic masculinity, etc) posed on men has multiple answers.
Being mentally strong is not exclusive with being physically strong. In fact both should enhance one another. You should educate yourself on how to best take care and enhance your body and in return you get better functionality which enhances your mental capabilities.