Thought about this a fair bit today, and I can't get behind her losing her show for this. First of all, she has apologized, several times, and I'm sure she means it.
I understand ABC thinks they are covering their asses and that Roseanne has caused issues with Twitter before, but this just isn't bad enough to me to justify the cancellation of a successful show. At least, this isn't where we should be counting coup in the political battle against white nationalism. Roseanne is a nut and has always been a nut. She's always going to do stuff like this.
Is the problem that she made a racist joke? Then no more racist jokes (which would be a shame).
Is the problem that the joke wasn't funny? Then no more jokes about anything controversial at all.
If it's the combination of racist and not funny, that puts a lot of pressure on public figures at a time when they already have a lot of pressure on them.
Leave the show on and see what happens. If the ratings tank, cancel it. I don't think they would.