I agree that the outrage is ridiculous. Comedians should generally get a pass, unless it's a flat out brutal attack on a race. However I still don't agree with it being an attack on free speech.
Corporate representation has always been a thing, this is nothing that just started recently with this current super SJW culture. Charlie Sheen got fired from CBS for saying "jew kike", dude from Grey's Anatomy, which is also on ABC got fired for homophobic slurs, those are just off the top of my head, I know there's a lot more.
Roseanne's boss also happened to be a black woman. It's reckless as fuck to compare a black woman to an ape when the person that signs your checks also happens to be a black woman.
Bill Maher also works for HBO, not ABC, two different corporate entities. HBO didn't care, ABC did. HBO is a station that also shows unedited content, nudity, cussing etc. ABC is a family network on regular over the air TV owned by the most family oriented corporation there is in Disney. Two different corporations will have different standards as far as how they want their corporation represented. HBO has been a champion of comedians for decades, was the first network that started to air hour long comedy specials, obviously they would give a comedian more leniency.
The thing is Roseanne still has her free speech, she never lost it. She can go on twitter right now and say whatever the fuck she wants, but that doesn't mean ABC has to have her as a representative.