It's all new users. Maybe the dev and his fanboys activated their troll bots. Probably that's how they used to cripple criticism on Reddit. However they should be aware, that's not going to work on Lemmy.
It should also be noted that c/syncforlemmy announced the need for mods (after their vehement criticism regarding the pricing). Probably they want to play a dirty game.
Many users would pay to have a subjectively better user experience. Sync was originally made for Reddit and had all that development time before Rexxit happened, and therefore, even after switching over to Lemmy, Sync is a more polished experience for many people compared to the FOSS alternatives.
I use Liftoff and Connect myself, and have never tried Sync. However, when Boost becomes available I'd love to try that out as well, as that was my Reddit app of choice.
These are the voyagers of me on lemmy my continuing mission to seek out new communitys and new fediversers to boldly comment where no comment has been left before