IMO you simply do not say those kind of things in public.
And if you were "brave" enough to say it, then at least stick to it. Do not pretend that you are so damn extremely sorry about what you said and you could not sleep at night thinking about it. All those apologies look really fake.
Anyone with a half brain understands that there are things that you should keep to yourself and not spread it in public, specially when you know that the company you work for, can easily fire you because of a simple tweet.