Unless it's changed recently users can enter Discord communities without an email via an invite link*, just choosing a username. It's what made onboarding so easy and similar to just joining an IRC server with a nick.
What's been ironic is since Freenode had their spam issues years back there was a push among many channels on that network to allow only registered users (ie: email tied to nicks) to post, which has continued over in the migration to the Libera network and I find really unfortunate for such channels of those networks as low friction and less permanence in ties to identity have been a distinguishing feature of IRC. (Obviously this doesn't affect IRC broadly but those are among the largest networks for tech communities).
Doesn't help with the issues around searching for data from outside of discord.