I understand how the internet works but you apparently don’t understand how people work. Normal people have absolutely no concept of how the internet works, they don’t understand what data servers need about them to function, or what a packet is. They need to be explicitly told that even though they’re using a privacy mode Google is still collecting data on them, especially since they’re collecting data even if you are not going to google hosted sites.
You’re infantalizing people by assuming everyone who doesn’t know how the internet works lacks critical thinking skills. Do you ever interact with non nerdy people? Additionally, some people do genuinely lack the capacity to understand how systems like the internet work, are we supposed to just let them get taken advantage of or exclude them from society?
I’m ignoring your last sentence because its entirely irrelevant to the situation, the data that Google was collecting from people using incognito mode is not data that they needed to make their services work.