Common sense really refers to herd mentality. Usually it’s correct like don’t jump in the water when there are sharks swimming around, or don’t eat the mushrooms you see growing on your lawn, that’s all common sense. But common sense isn’t always correct. Common sense in the late 90s was that you bought dot.com stocks, but look where that ended up. Like I stated above, common sense says that you don’t eat mushrooms growing on your lawn, but if you are a mycologist then you have specialized knowledge and can decide whether the mushrooms on your lawn are edible or not, even though common sense says not to eat the mushrooms.
The people on this board are not using common sense. It sounds bad, but it’s not. They are questioning the common sense and building their own specialized knowledge about the subject and making their decisions based on that, not common sense.
Sorry to get all English teacher on the term, and maybe I’m interpreting it incorrectly, but I believe that’s what common sense is.