Everyone here, including e.g. IT, uses HP membrane keyboards with not a whole lot of travel. They don't make noise. I grew up with a IBM keyboard. Only thing I remember is I loved the feeling of it because they keys were always under my finger. I don't remember how much noise it made. I guess it is different if you're the person who's typing.

Not every mechanical keyboard creates as much noise as the other one though. And it also depends on how you use the keyboard.

If I'd work from home, a MBP butterfly would make my partner insane though. It could wake up my child, even. If you make your own noise, it is might be soothing or something. If it is other people around you whilst you're trying to concentrate you are violating their ability to use their time efficiently. I'm of the opinion that we should value such as "extremely rude".