I would posit that Google is given slightly more leniency because their infractions always tend to be slightly less bad.
• Google tracks everything, but is ever-so-slightly more transparent than Facebook or Amazon, and the opt out process is ever-so-slightly easier.
• Google had their own version of the Facebook's opt-in but highly-invasive research app, but only for people who were over 18 (at least as of the past couple years).
• Android is kind of open source depending on your definition.
• Google left China the first time, whereas Microsoft, Apple, and others continue to operate in the country in compliance with Chinese censorship laws.
I am (very obviously, I hope) not saying Google is an angelic savior, nor that we should accept their actions. However, I do think people's slightly-better opinion of Google is more-or-less commensurate with the company's slightly-better track record.