Why should we condemn a person for good acts based on previous poor actions? Or are you just so cynical that you can't take his good actions in good faith?
The phrase "good faith" implies you can see into the mind of someone else. Whenever it appears, someone is trying to bias the jury.
The Gates Foundation is dedicated to "tactical philanthropy" which maximizes investment "leverage" by allying with existing commercial/political interests whenever possible, often with strings attached. Gates has stated clearly that he prioritizes programs that are revenue neutral -- that generate enough income to sustain themselves. While that's better than a stick in the eye, that's not exactly "giving your money away".
And in terms of atonement, exactly what remedial actions are sufficient to turn a gangster into a saint? Martin Shkreli and Al Capone would like to know.
I love that movie, but I don't get the impression he cheated anyone from it other than the guy who wrote DOS. Even then, it's not cheating to buy someone's product that you see potential in, companies do that every day. You can't really say he cheated Apple because they were both "stealing" ideas from Xerox.
Maybe you would also donate your billions to charity. Well, good luck earning them in the first place while playing fair.