In a non capitalistic future there would be other answers…

18 year olds are kids.

AIs do a lot of different things. What kind of AI do you mean?

Why do you assume the alien has access to the internet?

Pegasus != Unicorn

I found a server in the list I posted that was hosted by people in my area and funded by donations. I got in touch with them and they even implemented some bridges with that server. Now I am using it with a WhatsApp bridge, feels pretty seamless.

Why do not more people choose a matrix server and use a decentralized way of communication instead of committing themselves to this or that app/company?

Because most people they know use WhatsApp/Facebook/Instagram.