Fansplaining: defending an artistic decision by adding more context, in the belief that a critic will respond better if they have more context. The more context, the better.
Some arguments have more fansplaining than others. "You have to see the scene that comes next," is barely fansplaining. "It makes sense if you see the other six episodes," is typical fansplaining. "That's just one small thing in the larger canon," is very much fansplaining, as it doesn't even try to defend the original point -- just drown it with more context.
Fansplaining is not necessarily bad. Some things do have greater aesthetic value in context. Fansplaining rises from the fallacy that, "If only they saw as much of this as I did, they would appreciate it the same way that I do," confusing quantity for quality. Fansplaining rejects the notion that something
can still be good and flawed at the same time -- if part of it is good, then it's all good, and thus all of it must be defended.
Fansplaining is the ad nauseum versus
de gustibus.