The point of the lawsuit is essentially one: Mojang has a track record of being generally very non-trasparent with their ToS, which have hidden clauses and get regularly modified without notifying and (even less so) acquiring the consent of the customers, which is (according to the author of the video and his lawyers) an illegal practice under the European Consumer Protection Laws.

More in detail, the whole argument stemmed from Mojang trying to stop this guy from publishing a mod that introduces guns in the game, backing their decision on terms and guidelines separate from the ones availabe on the website and actually kept secret from the public as an internal document.

Another point of the video (and the actual main point of the Class Action) is the fact that Mojang used the same sneaky ToS update technique to secure the right of deleting accounts at its sole discretion with the aim of putting a deadline to the migration of Mojang Accounts to Microsoft ones, thus forcing EU customers to transfer their data from a European company to an American one under the fabricated threat of losing access to the game they purchased.