What they need isn't positivity, what they need is a tutorial. Right now, the barriers of entry for lemmy (and kbin and mastodon and other fediverse places) are too high for the common layman. They just want something that they can throw their names in and it just works. They don't want to know about federation and instances and how the fediverse works. They don't want to have to research the differences between instances and pick one that seems best for them, they are just going to pick a random one and expect it to see everything.
I want to share my first experience with the Fediverse. During the Twitter Exodus, I heard about Mastodon and, being curious, decided to give it a go. I installed the Mastodon app and tried to sign up, and I had no idea what the Fediverse is or what these instances are. I was expecting a simple signup process like Twitter. I was confused through the signup process, wondering why do I need to "pick an instance", what's the difference, what am I doing. Even after I picked an instance and got in, I had no clue how to find people to follow, how to see everybody's posts (didn't help that I barely used Twitter in the first place and thus was unfamiliar with this sort of place), why is my feed full of devs and programmers (I accidentally picked a tech industry themed instance randomly). It took too much time and effort to learn (and I wasn't committed or interested enough), so I eventually abandoned it.
Nowadays, I have a much better understanding of all this, lemmy is more comfortable for me, and thus I am having a much better experience. But for many who have no experience with the Fediverse, all of this is a lot, and it may be too much effort for them to dig in and learn how all this works. The general UX of lemmy needs to be streamlined and made, if not easier, then more approchable. Only then will more and more people be willing to join and participate in the Fediverse.