I figured Stark Raving Dad was not going to make the cut, but I'm honestly surprised that Homer Badman and Cartridge Family got cut out too, at least right out the gate.
All three of those episodes are beloved classic episodes that predated the modern controversies of today (The Cartridge Family was pre-Columbine, so mass shootings weren't the focus of the gun control debate at the time) and wouldn't it be easier for Disney to just put a disclaimer at the beginning of those episodes?
WWE Network did it with Chris Benoit footage, precisely because their previous efforts to censor Benoit's matches both infuriated the fans and created a Streisand Effect. They figured a disclaimer would just be easier for all parties involved.
Hell, doesn't Disney+ already have a content disclaimer on some of their older films like Dumbo or The Aristocats? Why couldn't they have a disclaimer for those episodes of The Simpsons?
I have a personal theory on why those episodes were cut out at launch. Disney is testing the waters and while the three episodes that were removed are controversial, they're also beloved by the fans. My best guess is that Disney is trying to see how much they can get away with their censorship. Have it start with Stark Raving Dad, Homer Badman, and The Cartridge Family, and then they'll try to move on to Natural Born Kissers, Homer's Phobia, and Much Apu About Nothing, etc.
Problem is that Disney may have overplayed their hand on the opening move. Had they just removed Stark Raving Dad at launch, but also kept in The Cartridge Family and Homer Badman at launch, less people would notice and there would be a much lower chance of backlash. Then Disney could more easily and incrementally remove any "problematic" episodes and few would notice until it was too late.