I live in one of the bluest cities in one of the bluest states in the US. And even here, the average Lemmy is nowhere near representative of the average person you meet in real life. If you think they are you are either deluding yourself or have an agenda to push.
Reddit is already an echo chamber and Lemmy just turns up the echo chamber dial to 100.
The real answer is that there is no platform that is perfectly representative of real life population. Everyone self-segregates into spaces they fee comfortable in.
Cascadia Now!