Well at this point I've gotten what I needed:
- DMs are going to railroad their players - with or without their knowledge. Some DMs apparently don't even realise they're railroading their players, and that's crazy to me. Again, this is because getting players to make choices they don't necessarily want to make is actually part of the game, part of the challenge of the game. If it's part of the game, it's not railroading. Apparently. But now that I know this is how people see 'The Game', a lot of things start to make sense.
- DMs author a lot of content - the game isn't necessarily as emergent as you think. Some scenarios, some locations, simply don't have a lot of options - even if you try. In fact, authoring content is basically a requirement of smooth gameplay, of having a smooth narrative. Otherwise players rock up to a location and nothing happens and that's just...Boring. Whilst I like to start my campaigns with a black map with nothing on it and make **** up as I go along (Emergent gameplay turns into authored content, I guess, in the vernacular of this thread)... Turns out a lot of people don't do that.
- DMs can do anything they want, it's intent that matters. Which means whether something is Good or Bad can absolutely be discussed. I know I've been called 'bad' several times and have been personally attacked at least once for pointing out several things that all DMs do, and then saying that the thing all DMs do, is the thing that they are currently saying is bad (e.g; Removing player agency).
- Players' immersion and suspension of disbelief is basically dependent on the amount of agency they believe they have, and if a DM is going to railroad and author content (which they all do), they have to hide their power level. After all; It's not a railroad if your players want to be on it. It's not authored content if your players can't see you reading from a script.
- Labels are basically meaningless.