Open hardware including motherboards exist, but why don´t they include a free BIOS?
That´s weird, because it it would be like that, there would be many computers with the RYF award. Why open hardware develpers don´t include free UEFI on their boards?
By "open hardware", do you mean hardware with free designs? You see, people who support "open something" often do not care much about freedoms. That probably is the answer to your question.
Well, free hardwareand open hardware are not the same. But free hardware motherboards don´t exist. Only open hardware.