Does personalization trump our SEO practices?

I have a question about how Google's personalization affects SEO. We all know that Google knows way more about us than we know about it. Google's big data algorithms are actually pointing us at content and ads that Google thinks we might want to click on or that we would be interested in depending on the information that we input and our past behaviours.

For the majority of internet users for whom Google is their main portal to everything they're looking for online, it is difficult to overstate the extent to which Google is controlling our experience by modulating the content we have access to.

Is there a problem with letting someone else decide what will be presented to us? I think there is, and the reason is because we're basically letting a corporation apply its own form of censorship to our web experience, which affects the information we're presented. I can totally envision a scenario where I'm a democrat and Google figures out based on my browsing habits that I'm reading a lot of Democrat political news sources, and it then stops showing me Republican sources ever because it thinks I'm not interested in those.

Now I'm in a situation where my opinion will never be challenged and the internet, which is supposed to help me access all knowledge equally, is now putting me into a positive feedback loop that becomes a circle-jerk of my own beliefs. We could be doing all of this work on SEO but Google has the capacity to show any results it wants to whoever it believes will click on the page - what does this mean for us as we try to promote our blogs, websites and products?

I have even heard of scenarios where Google was serving somebody ads based on a verbal conversation they had, indicating that the microphone on the cell phone was somehow being used to pick up information from conversations and manipulate or influence search data. Are we ever really alone? Are we ever in control of our own browsing experience? What do you all think?