We could have "rational thinking for teachers", a "rational thinking for programmers", a "rational thinking for musicians", a "rational thinking for women" and a "rational thinking for teenagers" group. At the end you have 10 different groups.

It depends.

If the Discussion page gets flooded by dozen "rationality for musicians" articles, it could make the members without musical interests feel excluded. One such article in a few months would not have the same effect. And it could make the musicians very happy.

One can be more specific about "applied rationality for musicians" than about "applied rationality for artists", which is still more specific than "applied rationality" in general. Perhaps we should replace "rational" with "optimal" here. But anyway, the goal of rationality is to win. We can win more by sharing the fruit we already found; even if doing that does not directly increase one's fruit-seeking skills.

(Personally, I would love to see the "rational thinking for programmers" topic, but I am afraid that this topic has a very high chance of jumping to a dozen articles per month when the taboo is broken, so I will rather not break that taboo. But writing for teenagers seems much safer.)