"Does the audience change the message, or the delivery of the message?"
If you habitually access the Internet with cookies enabled, and use Google to search, the search results will be "helpfully" tailored to your past online activity (on which Google will have copious data). So, should you ever idly delve into a rabbit hole, Google's algorithms will deem it to be one of your interests. Is it any wonder that misinformation gets reinforced and proliferates?
There are times when cookies are essential: accessing bank accounts, buying online, and (as now) commenting on Web sites. The data-culling can be limited by NEVER accepting third-party cookies -- but how many users are aware of that option? And, even if they'd read about it, decided that changing settings was too much hassle. Also, very few users are aware of anonymised search options such as Startpage and Duckduckgo; the general view is that to search means to Google.
I don't see an easy way out of this Google strangle-hold. Culling personal data is their money-making objective. Disseminating reliable information and proven facts in response to a search query doesn't figure in their equation.