Lol what will you say them? Your IP won’t be shared to other websites, but only to Google, switch your browser now! That will be so dumb…

I won't tell them much. I will suggest they read it and let them know I will gladly answer any question they may have after reading it.

They're just ignorant of the technical considerations but they still have a fully working brain, and given some lead they should easily understand the topic at hand (a bit like, say, if I discussed the differences in the process of painting watercolor versus oil or gouache while you have yourself never painted a canvas in your live I would not consider you too dumb to understand, or laugh at you, I would instead take some time to explain you what are those essential differences and why they matter. Well, this article will do exactly that in regard to Google, for those persons).

As I wrote in my first comment, this article is a nice and clear summary of the issue (Google privacy-washing) and should help them understand or, if you prefer, realize that this issue may be worth getting more into it. Then, could begin our discussion.

Don't you agree that understanding there is an issue is a required starting point for anyone to take any decision in order to try to correct said issue?

As for the rest of your well thought-out comment, here is my take: I hope they will change, and not just their browser, but I certainly will not tell them to change or to do anything they don't want.
I know we live in this strange new world, where hostility and mockery is becoming the norm, but barking orders or Loling at the face of people is not what a discussion is supposed to be. Maybe that is something that's worth repeating, no matter how dumb it sounds.