It seems that someone put a bunch of common explanations on a web page and stuck the word "fallacy" after all of them so that they could use it to try to win arguments with easily-intimidated persons.
Many situations exist wherein a series of steps could superficially be arranged in a progression or slope between points a and b but in fact individual steps have different costs and benefits and are in fact independently good or bad.
Often those arguing for/against a subset of the points in the graph have good arguments for/against then some jerk goes and implies that if you allow point 1-3 on the graph somehow by magic you will eventually arrive at point 37. They ignore the fact that its possible and in fact reasonable to support point 1-3 and skip right to the extreme and absurd.
They neatly bypass any and all relevant arguments in favor of 1-3. This is destructive to conversation because you can use it in nearly any situation. It is especially frequently used in anything involving government because somehow all roads that don't lead to anarchy somehow lead to hitler.
Its frequently useful to just point out the obvious fallacy and move on rather than giving a longer treatment because such tracks are frequently useless and drag the entire discussion inevitably towards stupidity.