I'm no paragon of maturity or stoicism, but I'm not wholly ignorant of the concepts, either, and I think there's a large overlap between the two concepts. Mature people should be slow to get upset about things that don't actually harm anyone, and stoicism is based on the idea that while we can't always control what happens around and to us, we can choose to control our responses.
There is real emotional and physical value in being emotionally controlled, because stressing out over things we cannot control is not healthy, emotionally or physically.
Maturity and stoicism seem to come naturally to some people, but for others of us it is hard, requiring intent and conscious effort.
Getting bent out of shape about the networks' obsession with showing Swift at football games - as silly as that cultural moment truly is - is among the least stoic and least mature responses I can imagine. There's no actual harm done to anyone. I can understand mild annoyance (although bored disinterest would be better), but nothing more.
I think there must be for some people a desire to be outraged, or in economic terms a preference. But I have a suspicion that there's a big overlap between this group and the group that likes to snarl "fuck your feelings" at other people.
I won't say "fuck your feelings" to Swift-haters, but I do think they've actually fucked themselves, and they'd be happier people if they could just find this cultural moment and the media's predictable inability to control itself with the detached amusement that it properly deserves.