I think it wouldn't be toooo far of a stretch to say this was hacked. I found a user with your reddit name (Eastonator12) in the Nintendo Homebrew discord, which implies you are no stranger to hacking.
Someone made a good point here: "Why did they take an obscured picture of their TV (shown in OP) when they claim they're playing the Switch version and just didn't use the screenshot button..."
His video (I honestly wouldn't even give it a click) Ganon fight Ganon fight spoiler (youtube link)
Ganon is not a spoiler, he's on the back of the fucking box. If someone is really that sensitive that knowing Ganon is in the game 3 months after it came out bothers them, then I'd think they'd avoid BotW threads.
There's a lot of people hacking the Wii U version and claiming they found some secret area or super glitch. I generally wouldn't trust any claims like this without proof it's on the Switch version.