I already searched for this but it doesn't really contain what I'm about to ask.
The slippery slope fallacy, according to Wikipedia's definition, is "a logical device, but it is usually known under its fallacious form, in which a person asserts that some event must inevitably follow from another without any rational argument or demonstrable mechanism for the inevitability of the event in question. A slippery slope argument states that a relatively small first step leads to a chain of related events culminating in some significant effect, much like an object given a small push over the edge of a slope sliding all the way to the bottom."
But putting it into actual practice, no one who uses the slippery slope thinks their progression of events is irrational. A rational sequence of events wouldn't be considered a slippery slope. This definition seems to be heavily subjective, unless they're using the formal-logic definition of the word "rational". In any case, without this requisite, any argument that argues long-term consequences from short-term actions falls under this fallacy, which is absurd.
It seems that the way to handle this is to show that their argument is irrational instead of claiming it's a slippery slope. Simply showing that the argument is irrational would suffice. Claiming it's a slippery slope doesn't work if the person believes their argument is rational. So is there actually a point in ever claiming that someone's argument is a slippery slope?