As someone who has raided extensively in WoW as well as a ton in TTK-era Destiny, the sensitivity towards 'spoilers' took me off guard.
In WoW, you're expected to have read up and watched videos on every fight. Not everyone does it, but at the very least you'll have a few dedicated players who studied or even did the fight on PTR and can explain it well.
I've never been good at reading or watching but I learn very fast by doing the encounter myself. But I still feel obligated to at least read over the mechanics, and I started doing this before going into the King's Fall raid but my group actually got pissed when I mentioned reading up. I was completely baffled by this especially considering the absurdly obtuse nature of some of the mechanics and puzzles.
That said, I kind of get why. The moment when the 'real' Oryx fight starts was very memorable and none of us expected it. It was kind of fun puzzling some of that stuff out. But the only reason you can get away with it is because Destiny raids are small scale and comparatively easy compared to a traditional WoW raid.
I'm holding off on watching GB play it because I guess Destiny players rubbed off on me. But I'll be bringing WoW players into the raid and I'd imagine they will be like I was, and just look everything up because they'd feel like they were holding the group back if they didn't.