Editing to let people know that I will be blocking anyone who feels the need to tell me why this graph is inaccurate. I truly don't care, but feel free to chime in with your useless take and land a spot on my block list! ๐
I don't know about that app specifically, but I know some fediverse apps do not have all instances in their directory. For example, fedilab doesn't have friendica.world. I would suggest hunting around for an app that supports your instance, but I agree, it is a dumb problem. What is the point of being able to join whatever instance you want if it is not listed on the app?