It sounds like people are just saying stuff without trying it. If they haven't tested it, then they can't know for sure. The people that you talked to at Gigabyte or Intel sound like they have no experience or actual product to test.
I was thinking about asking people in other recent Gaming 7 threads in this forum to report on their Thunderbolt experience and status in this thread...
I've ordered a Thunderbolt 3 device to test this before I start complaining to GIGABYTE, Newegg, or Intel. The only device available currently is the AKiTiO Thunder3 Duo Pro. Actually, if you had another GIGABYTE motherboard or another thunderbolt motherboard, then maybe you could connect them to test. Gigabyte should have plenty of motherboards to try that...
Another thing that needs testing are the alternate mode adapters (DisplayPort, DVI, etc). I know the USB 3.1 part is working. I know someone with a MacBook - I'll ask to test some of the adapters they have (even though the MacBook doesn't have Thunderbolt, the adapters should work - maybe?).