It’s because a few months ago they shut down several fan animation channels and creators, and scared others into shutting down, all to get rid of the other animations to drive people to their pay to view Warhammer+ animation thing.

(one was offered a job by GW, and turned it down, only for them to bully Patreon and YouTube into shutting down his channels and ruining his work)

A couple animators were hired and while some went on to continue making great work, others immediately saw their work changed and managed to fit GW’s ideals.

TL:DR: They and their actions bullied every fan animator who didn’t want to work for them into shutting down, just yo make sure people would have to pay GW to see any animations (which can now be found on Warhammer+)