I think your reasoning is flawed, to be honest. If a person (and let's pretend companies are people, just for now) does something amoral, it would take a lot of deliberate effort to rebuild trust in said person. Especially so if the deeds were done in a situation where the person was in power and that power has since dwindled. Of course, companies aren't people, but even then - The actual people who lead the company are, and those are the same people now as then. For comparison, I think mr. Gates has actually done his part to "repay" his debt to the world, but that's him personally - not something that reflects back on Microsoft.
In any case, the topic wasn't about which is fair or not, but rather about what the public image of Google vs. Microsoft is and I strongly disagree with your sentiment that Google generally appear more corrupt than Microsoft does. At least if we're talking the tech-savvy part of this worlds population.
