If a man had posted that tweet, their firing would not have been notable and the internet would not be calling for boycotts, 'justice', apologies nor issuing death threats.
And if the tweet had still somehow garnered a lot of attention and gotten someone fired, he would have been condemned much more strongly for lacking the basic human decency not to out someone publicly, lacking the empathy to express regret over a man with a wife and three kids losing their job, and not manning up to admit they didn't handle the situation appropriately.
In other words, if a man had posted that tweet, he would have received much worse treatment, because this has everything to do with the tweet being an inappropriate reaction to a silly joke, and nothing to do with discrimination against women.