In its ideal, most reasonable form, and even in the diluted form espoused by rat[ional]ists, I don’t personally have any issue with the concept of growth mindset in and of itself. It seems no different than any other form of naïve optimism, power-of-intention handwaving, or placebomancy—but precisely because of this, I feel it falls short of its mythical status as received wisdom.
I’ve noticed that rats have a tendency of venerating concepts like this in a scope that far outstrips what the original (evidence- or logic-based) formulation was used to denote. To me, there’s no big problem with that. All groups of people share some sort of mythos, or things that “everyone knows”. Demanding that all of these sayings and mottos and dank memes be based on dispassionate statistical analysis is not only unreasonable, but an obstacle to making progress.
However, I think that we had better become mindful of the fact that our memes are not substantially better, and we are, most of the time, not substantially wiser than members of any other subculture when we try to apply them to reality—or we run the risk of digging ourselves into antics far more absurd than even the most foolish “normie” could dream of!
I don’t think the common usage of it is about placebomancy. Take social skills as an example. A lot of nerds are bad at social skills.
A nerd without growth mindset would say: “I’m just not talented at social interaction” and doesn’t do much to change it.
The growth mindset nerd doesn’t say: “I will just get better if I believe that I will get better”. He rather tries to research how social skills are build and then does what needs to be done to build the skill.
In a similar way the mindset leads to our community generally doing more sport than other nerds because we don’t let a nerdy self-identity get into the way of physical exercise.