Well wait, deplatforming is when a platform drops someone. That's separate from the "mob rule" of large groups of people criticizing a person or entity.
Someone can have their public reputation tank over a tweet, sure, even without malicious intent. I feel like that happened more often when there were fewer easy targets. It's also a natural element of public relations. Public figures have always been held responsible for gaffs. The difference is modern technology and culture encourages them, like the rest of us, to overshare.
And what Carano did wasn't just one gaff. Her pronouns "joke" could be a gaff, that image which was clipped from an antisemitic image could be a gaff, and retweeting anti-mask and election-fraud conspiracies could be gaffs. That's a whole lot of gaffs, which should and did result in backlash. Her response was to compare that backlash to Nazis preparing the Jews for genocide.
I am under no obligation to shut up about how her takes are awful. All else being equal, I'd rather not support a company that hires her. Am I wrong to make that choice in the literal marketplace of ideas?
No one is "popular until proven bad". If people don't like you, they don't like you. Gina Carano has made her opinion about people like me abundantly clear with her very loud platform. I don't have a comparable platform, and I'm not obligated to like her.
Though I don't know of her inciting violence or anything, so I'm fine with her still tweeting? Just to reiterate, deplatforming is a completely different tier than merely being offended by someone's naked hatred of me.