No, according to your logic, they should exclusively use profanity, and not mention something like "wetting themselves" once in a thousand speeches.
So, why did he blow up the cafe along with Vasya, just because he swore a lot?
Our brain is a very delicate and complex matter, a learning neural network, and the quality of its work depends on the information it receives and its receptivity. If you keep pouring advertising into people's ears, they will remember the brand, and if they are not inherently skeptical, they will most likely buy it. If you spread propaganda, you can move the masses, and that's how revolutions are made (of course, with money and weapons... But also with repeated nonsense). Words have power because that's how the brain is structured, physically. Naturally, negative words that carry negative emotions, often consumed and often repeated, can easily and actually make a person's life worse. If you reinforce your dissatisfaction with neural connections, that's a real trap of bad mood, don't you think? And it doesn't matter which factors are more to blame for this bad mood; even if the environment improves, the trained person may not be able to unlearn it so easily... And conversely, there are people who endure greater hardships than ours without falling into despair: they are not made of different stuff, no, they just have a different algorithm of action.
But most importantly, I don't understand the logic of "why not indulge a little, if everyone around is indulging much more." Profanity is already unpleasant enough to avoid it. Otherwise, you could say: well, everyone is walking around, covered in garbage from the landfill – let me just get a little manure on my pants, it's not that bad? Well, it's not as bad, but what's the point if you can avoid getting dirty? It's always nicer for you and those around you to look at clean pants.
Sorry for the boring lecture, but I don't know how else to say it... And I didn't discover anything new, it's all very obvious 😣