You already know from your experience what you will say to the idea that Bitcoin maximalism is an echo chamber. The idea that we just arent open minded to crypto ignores how many of us started in, and got burned by crypto. I've written a more well thought out response to the anti-bitcoin maximalism crowd so that otherwise quick witted responses they're used to don't turn off their critical thinking skills.
Please feel free to modify in any way you see fit so that your experience is reflected in it, but I hope this article will help you form better arguments with the people you engage with: