I read somewhere that the perpetuators are likely getting some practice in before attacking their actual targets. Lemmy instances just happened to be unlucky enough to be among the victims chosen for this rehearsal.
We have very different perceptions of how people approach emails.
Guess how tech illiterates(?) approach email? They sign up on Gmail - perhaps with some handholding - and that's it. That's all they know or care about.
And before you say they don't deserve to be on the internet: they are all using Facebook, Youtube, Whatsapp, etc. Unless platforms like Lemmy actually treat new users better, there's not much incentive for people to switch.
It's not just you. Perhaps it depends on the distro?
I just had to click around a little when setting up Ubuntu 22.04 and it's done.