There's railroading and then there's *railroading*.
It's all a matter of style more than substance I think. But style counts large in terms of player enjoyment.
Any campaign arc is necessarily path based and inherently "railroadish" in nature. That does not mean that it needs be inept and to jolt the player from the enjoyment of the game by constantly revealing the man behind the curtain. For DMs, it is a learned skill. (the DMG II has a few things to say on this in Chapter 2)
It's more a matter of accommodating different and unexpected player choices and still keeping things reasonably on track and seamless that defines a good railroad from an inept one.
I believe the a strong plot focussed campaign with an artfully done railroad is the very height of DMing and provides the strongest enjoyment and fondest memories for characters.
At the same time - there are players who get simply *incensed* with the idea that ANY pre-planned adventure is afoot at the table. Once they smell it, they take it as a challenge to their freedom and go out of their way to ignore anyhitng that smells of pre-planned adventure.
I had a plyer like this once; my best friend as it so happened. We don't game together anymore.
It comes down to a matter of preferred style.
Story focused = good; railroad = bad
plot =good; metaplot = bad
Certain terms tend to be used in the pejorative, others in the positive.
That's a pretty clear indication that politics and values are behind the analysis and terminology.