We've lived in that world for at least 20 years. Google already "decides what you should know" every time it delivers search results. It's not deciding based on morality, but rather which information will make you more likely to click an ad that makes it money.

Any free service you use to find information is deciding what answers you should receive. Facebook decides what you should know. YouTube decides what you should know. Twitter decides what you should know.

But if you're curious enough, you can keep pecking away at these services to give you information that you consider to be high quality and not just the first and easiest answers.

AIs aren't going to blackhole information, unless there's a financial reward to the owners of the AI.