There's a trope in cartoons where a character will think forward to the future, and they're about to receive some honour, like graduating from university, or becoming the president, when someone will suddenly interrupt the ceremony, bring up something arbitrary, and the character will end up befalling some horrible fate. Here's my favourite example of it:
https://www.youtube.com/watch?v=LOMn06mIKvM
In this day and age, where what you post on social media matters more and more, one mistake can ruin your entire life. People have always said dumb shit, but it's easier than ever before to document it in the age of digital information, and hold it against them forever. I'm not defending Roseanne (I've been critical of her and Trump in this very thread), but I do think real life consequences over dumb shit said on social media is a dangerous precedent we're setting. I'm fine with ABC making the decision to get rid of the show, because she said this whilst contracted, but I think over the next twenty years, with a new wave of celebrities, people will be combing for old social media posts to shame them with.