Sorry, they ARE for HDMI "The manual says the ferrite cores provided are for HDMI (2) and USB Keyboard (1) they say that these can help reduce electromagnetic and radio frequency interference. They may not make any difference to YOU but your neighbors might thank you for using them."
I had to look information up on them yesterday to learn this.
I honestly guessed the manual would say the same as my 2010 Samsung plasma manual, weird.
All my Monoprice HDMI cables have ferrite cores at both ends, I think it's for the benefit of the cable, the wiring inside HDMI is so very thin.