Your idea sounds like something that independent journalism can pick up or some non profit organization that exposes these kinds of things. Of course I'm sure someone will go after them sooner or later.
Individuals and companies knowing more information about the professional history of the people they're doing business with is always better.
I get your point though - I'm just more inclined to believe this would be used for good, rather than evil. I also agree that people should have a chance at redemption.
I think you might be over-stating the effect this would have. Most people won't care. And if Elon Musk is any indication, having a bad reputation only hurts so much if the offering is compelling (eg. Space-X, Tesla). Both of those are huge successes despite Elon having a questionable reputation personally and professionally.
Note - I'm making no judgement here - I'm just talking about the consensus opinion on Elon as I see it.
(Similarly, in a much better world a politician who had changed their mind or did not have an informed opinion would need to say that out loud; but when I teach—smart, motivated young adults!—I have to make them unlearn so much fear of being wrong and shame of not understanding things that I can’t see admitting ignorance working out in real-world politics.)
In narrower circles, this could probably work. Amazon is already forced to pay newly-hired programmers above market rate, I hear,—would a former Amazon executive need to?
2. Most startups fail, they tend to abandon their customers with little or no warning, and then write a boastful blog post like it's okay and normal to throw away what could've been a business to someone else if they tried to find a home for it. To me, that's disrespectful of both investors' and customers' time and money.
3. Most "brands" on Amazon tend to be meaningless nonsense because a reseller overseas decided to satisfy the need to call it something and just pick whatever because they don't intend to stick around. As soon as people find out they're selling junk or they have a problem, they throw it away and pull another brand from the disposable brand box.