While Jitsi is open-source, most people use the platform they provide, meet.jit.si, for immediate conference calls. They have now introduced a “Know Your Customer” policy and require at least one of the attendees to log in with a Facebook, Github (Microsoft), or Google account.
One option to avoid this is to self-host, but then you’ll be identifiable via your domain and have to maintain a server.
As a true alternative to Jitsi, there’s jami.net. It is a decentralized conference app, free open-source, and account creation is optional. It’s available for all major platforms (Mac, Windows, Linux, iOS, Android), including on F-Droid.
Law enforcement can subpoena Google for breadcrumbs, and then go to data brokers for the missing pieces. It’s not perfect, but this likely isn’t the reason for Jitsi doing this.
The real reason likely falls along the line of the extra requirement driving people away from misusing the service, if they now need a VPN + killswitch and a burner “faang” account to share illegal content. They’ll just go to the next common denominator sadly, resulting in truly anonymous services dropping like flies (anonfiles.io being the last example of this)