Not talking about it doesn't automatically mean someone is handling something without issues. Many people don't talk about things either due to trauma or because it's just socially disincentived to talk about something. Some of the worst things fester because people don't talk about it.
There can be an overabundance on the other side of ruminating too much on a topic that is also unhealthy as well and I can see admiring people who've survived hardship well, but it's important not to pretend that even that not complaining somehow means anything about how someone is doing. Some will be doing well, for some that commiseration helps, some will be quiet but turn to drink, other drugs, risky sex or other vices as a coping mechanism, others turn to religion and other ideologies, some mix it up in finding a way to get pleasure, meaning, and interest in the suffering of life.
I find the idea that others suffered means I shouldn't complain odd. During the worst parts of my life, I often found the littlest things to be upset on. I didn't have the energy to complain about the horrors going on or wouldn't dare give it words, I was too frightened because no one else was talking about what seemed so obviously bad so it must be too much to discuss. It took me years to get over that.
It took my MIL ten years to cry over her father's death because, born just after the WW2 and went through a lot as a career woman, it weighed on her a lot that she must keep a particular image. Couldn't be seen as weak, couldn't be seen as needy, she laughed when her disabilities acted up, and some might thing she was stoic. I don't think she was. She was an admirable woman in many ways, but I think she was scared for people to see any softness, even her own family. That affected her health and relationships in many ways. I think there is a balance between the hard image she was trying to portray and letting out an overabundance of every emotion that I think she feared.