Agreed, but consider this: a slippery slope fallacy is more like "If we do A, then B will inevitably follow". Lacking evidence to support it, that is a fallacy. But it's not a fallacy to point out "B" as warning of what might follow from "A".

And in the "reasoning by analogy" sense, it's not wrong to point out that "Group C did A and then B followed, so we might want to be careful about doing A" (assuming "B" is something undesirable).

Sometimes it is a valid point of discussion to point out these potential "slippery slopes"; it's just important to distinguish between the assertion that the following part happens as an inevitable consequence or not, and if that is asserted, to demand evidence.