Your experience is that "non-lifters" are the aggressive ones fixated on beating people up? I don't think that would match most people's experience.
And I highly doubt concealed carry leads to more polite interactions.
Also the level of aggression in the weight room is extremely low compared to the basketball court. You "win" in the weight room by lifting something heavier then fist bump your friends, lifting is not a zero sum game, in theory everyone can win every week if they're making gains. The only way to win on a basketball court or similar, is to dominate a the weaker into taking a loss, its a zero sum game.
Very rare in media to hear about a fight breaking out in the free weights room; fights happen every day at basketball courts, hockey arenas, soccer stadiums ... team sports are super violent.