C++, especially before C++11, was a total mess. Even today, it's super easy to shoot yourself in the foot and you literally can't learn the entirety of the language due to how massive it is. This still doesn't justify doing the absurdity of macro magic and garbage I've seen people pumping out in C over the years though.

IMHO if you deliberately use C it's because you want to keep things simple. Sometimes C++ will inevitably lead to overcomplicated designs nobody needs; there's a reason why 90's C++ feels massively outdated, while 90's C is still (mostly) accessible. C is a great way to keep the urge people have to shovel in OOP even when it doesn't really make sense. When I see some bullshit C++ code at work, I often think, "if people had to write this in C, they wouldn't have overthought this this much"...

My 2 cents is that there was a Java craze back in the '90s that basically infected all code designed in that time period, and that's how we got some very weird nonsense that in hindsight was poorly thought out. Just look at stuff like GTK+ and GObject...