"if you don't like where you are, go make your own instance" is uncomfortably like "if you don't like your neighbourhood, build a house somewhere else" -- it presumes a whole shitload of privilege and resources.

Instead, it's much better to point people to the list of instances, e.g. the list of essentially free housing they can trivially move to. Just think before you say "just do [enormously difficult technical thing] lmao" like it's eating ice cream.