Are you under the impression that people who teach logic are unaware of real world evidence that "things change and some of the those end up being bad"?
A slippery slope is a logical fallacy. There's not a colloquial version of that term that means something different. It's a style of argument, where you asset that one action will lead to another action without any evidence of a direct casual link between the two.
Second, I'm not appealing to authority. You said a slippery slope isn't a fallacy. I provided a link which makes the case as to why a slippery slope is considered a fallacy.
We are not using "slippery slope" in any way which is different from the examples given.
That one thing has lead to a bad thing in the past is not evidence that this thing will lead to this specific bad thing in the future.
Yes, sometimes, slippery slopes end up being slippery, and sloped.
But that doesn't mean anyone has to take it as a given that any other specific slope will be slippery, nor slippery in some specific way which leads to some specific outcome.
