Here's the thing, your example is describing what happens when the GM's railroad is being actively fought by the players. Your attempted example of a player side railroad is actually the thwarting of the GM's planned railroad. If you described this play absent a planned story the GM is telling, it's unremarkable. The only power your example has is that it showcases that players might be able to buck a railroad by being disruptive. You ask how the GM can counter this without engaging in railroading, but you started with the GM railroading -- it's already there.
As for using the term, it's used to describe play that most find unpleasant and disliked. I see no need for it to not carry negative connotations.