They jumped when they made 10-year-old Lisa the one and only "intelligent" character with any supposed morals or virtue.
Coincidentally, they also re-made her into a Hillary Clinton politically-styled b*tch.
I have actually conversed on this forum with those that insist that "The Simpsons" is a conservative show. I simply have to point out Lisa who is billed as the "moral center" of the family. Cased closed. I still enjoy watching the show, but have learned to hit mute whenever Lisa climbs on her soap box.
Once they started injecting politics into the show it jumped.
Lisa is like a radical leftist and the moral center of the show and the smart one, and that made it annoying.
Unless your a left wing politically obsessed person, who drinks, eats, and sleeps leftism, your going to get annoyed with the heavy doses of politics in the show.
It was much better when they tried to center the show around the family, with Homer being a caring dad (as opposed to now where he is both stupid and selfish), Marge being a good mom, and the kids bickering and fighting but still able to come together.
Now the show is just over the top and seems more concerned with getting cheap shots in on a big chunk of its viewers.