Because of HDMI-CEC. The dongle can control things on the TV via this technology. This product specifically has a remote that I believe only interacts via HDMI-CEC.
I don't know if it's possible for the HDMI-CEC to pass through a receiver to the TV itself for this purpose.
I don't know if it's possible for the HDMI-CEC to pass through a receiver to the TV itself for this purpose.