I think it's more than fair to say that we all give a lot more rope to our favorites than someone of whom we aren't a fan.
Take a song like Thank You Aimee. If someone had gone out of their way to ruin the reputation of someone in DT with a doctored phone call and they wrote a "diss" track about said person 8-9 years later, would we all be like, "eh, they should be over it by now." Hell! No! We'd all be like, "hell yeah, they deserved it!" So, I don't see it being a problem in the case of this song and Swift.
Also, there are layers to that song; it's not just an FU song. There's also a bit of "you tried to destroy me and look at me now!" to it (a bit of comical hubris), and there is also the shift to "thank you" in the final chorus, which feels like an acknowledgement that Reputation, an album of which she is very proud, would never have happened the way it did without the two unmentionables doing what they did.
Is she overexposed right now? Sure. I get that some are tired of hearing about her, but is she supposed to stop releasing new music because some are tired of her? She is obliterating records left and right, so it's clear that many are not tired of her. She became the first artist to get a billion streams in a single week in Spotify, which she achieved with still close to two full days left of that week.