Just to play devils advocate, there IS a reason why he is calling himself a cyborg and not someone with cochlear implants or a pacemaker. Those pieces of technology fix or enable senses that the person already has, fixing problems with systems the body already has in places. This thing gives him the ability to hear colors, an ability that he wouldn't have even if he had no handicap. And yes, Synesthesia is a thing that some people have, but that doesn't mean that it doesn't count as an extension beyond his normal ability: if a brain implant gave someone perfect memory, id count that as a cyborg even though there are people who have that ability naturally.
Ill agree that it is a pretty underwhelming cybernetic for someone calling themselves the first cyborg, but it only makes sense that the FIRST would be a pretty crappy enhancement, and better ones come later. I may in general be underwhelmed, but I DO think the very fact that we can say that a Cyborg Foundation exists is about the coolest thing ever.