Yeah, conflating an adventure that's on rails and "railroading" seems to be really common lately. The idea that you've got a straight through-line through your adventure without a ton of options how to proceed differently is not only pretty common, it used to be pretty explicitly how you'd run a game. Most published adventures would start you off, give you a goal, and most of your options on how to complete it would be like a video game; you might talk your way out of a confrontation or you might fight your way out, or you might sneak past it. Simply avoiding it altogether though? Not really an option, or if it was, it was only because you could choose one of two or three "tracks" to get to the same endpoint. "Sandbox"-ier games did exist and even sandbox-style published adventures existed. But they were decidedly less common and certainly not the expected product.
Frankly when I'm starting a campaign, I tend to start off with a short premade adventure in this style anyways. If the players don't gel or find they're not interested in D&D, or we just can't get a schedule together, then I haven't invested a ton of time in building a playhouse that won't get used. But also being able to hold new players' hands through the really overwhelming part of learning a whole new system and a character and also coming to terms with the things you can do in a TTRPG, by limiting their options to "one way in, one way out, follow the tracks and you're going the right way" is just one thing they don't need to flounder through. If it sticks and they like it, then when the first part of the adventure is done, then they get access to the bigger world and can start to make decisions about what they want to do and where they want to go.
My parents really liked Ticket to Ride and Qwirkle. Much more complicated than that, though, and my dad starts pulling faces.